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Daily metabolism and hepatic balance studies of plasma cortisol and aldosterone in the preruminant calf
DALLY METABOLISM AND HEPATIC BALANCE STUDIES OF PLASMA CORTISOL AND ALDOSTERONE IN THE PRERUMINANT CALF M. Gardy-Godillot,, M. Dalle,, D. Bauchart, b D. Durand, b a n d
P. Delost. •Laboratoire de Physiologie Animale et UA CNRS 1123, Universit~ Blaise Pascal-Clermont-Ferrand II, Ensemble Scientifique des C~zeaux, B.P. 45, 63170 AubiEre, France; bI.N.R.A. Theix/Clermont-Ferrand,63122 Ceyrat, France Correspondingauthor: M. Dalle ReceivedJanuary 6, 1988 RevisedMay 10, 1988
ABSTRACT Intestinal and hepatic catabolism of cortisol and aldosterone were studied in the calf using blood samples from the mesenteric artery and portal and hepatic veins collected over 24 h, the hepatic blood flow being continuously recorded during this period. The total hepatic blood flow remained broadly constant over the 24 h~ a].t~cu~ meals were followed by decreasing flow in the portal vein and by increasing flow in the hepatic artery. The intestinal tract catabolizes cortisol as intensively as the liver (both 13% of cortisol reaching the organ). The part played by the gut and the liver in the catabolism of aldosterone were also equivalent (both 30% of aldosterone reaching the organ). This 24-h study demonstrated that a constant ratio existed between secretion and catabolism of cortisol while the hepatic balance of aldosterone seemed to be modified during the night. INTRODUCTION Although the liver is usually accepted as being the major site for the metabolism of cortisol (1), there is evidence that other tissues are able to change the structure of steroids. Cortisone was the major metabolite produced by all the experimental tissues, in vivo and in vitro. The kidney may be an important site for the metabolism of cortisol by oxidation to cortisone (2,3); however, the relative metabolic clearance rate of the kidney for cortisol remained much lower than that of the liver and the gastrointestinal tract (4). The lung has been implicated in the metabolism of steroid hormones (5) and the presence of 118hydroxysteroid dehydrogenase activity has been reported in the lungs of rats and
STEROI DS 53/1-2
January-February 1989 (49-58)
49
50
Gardy-Godillot et al: CALF ALDOSTERONE AND CORTISOL CATABOLISM
guinea pigs (6,7). However, demonstration of the pulmonary metabolism of ~ cortisol in vivo has not yet been achieved. The intestinal metabolism of cortisol has also been demonstrated in the dog (8). Nevertheless, all these studies could not be easily translated to the physiological event occurring in the conscious animal. An approach to the problem of the cortisol metabolism in the conscious animal has been described in the sheep (9,10) with the measurement of cortisol dynamics after radioactive cortisol infusion. Metabolic balance studies involving the combined measurements of venous-arterial concentration differences and blood flows have been tried on dairy cows (11) and preruminant calves (12) and sheep (13,14). As intermittent values of blood flow gave only
a general idea of the
function of an organ, we have undertaken to sample blood regularly from the mesenteric artery and the portal and the hepatic veins to measure the cortisol levels over 24 h, paralleling a continuous recording of the hepatic blood flow using the preruminant calf as a model (15). Thus, we have investigated daily cortisol metabolism in the gastrointestinal tract in relation to the hepatic balance of cortisol and aldosterone. To our knowledge, no investigation of daily aldosterone metabolism and hepatic flows has previously been undertaken.
MATERIALSAND METHODS Animals The study was carried out on five 2-week-old Friesian-Holstein male calves weighing 45 + 3 kg. They were fed a milk substitute containing 22.5% tallow and 23% protein twice daily. They were bearing indwelling catheters implanted in the portal vein, in a mesenteric artery, and in the hepatic vein. Electromagnetic blood-flow probes were placed around the portal vein and around the most accessible branch of the hepatic artery. Surgery and blood flow measurement were
STEROIDS 53/1-2
January-February 1989
Gardy-Godillot et al: CALF ALDOSTERONE AND CORTISOL CATABOLISM
51
described (t5). Blood flow was calculated from the graphic recorder, Ibe flow probe regression line established before surgery and the conversion factor were determined from variations in packed cell volume. This technic of electromagnetic flowmetry gave results in complete agreement with dye dilution assays. The mean values obtained in 2-week-old calves were similar to those measured in older animals (3- and 5-week-old calves) and remained constant during a 3-weekperiod. During a 24-h period between 8 AM and 8 AM of the following day, 29 3mL-samples of blood from each of the 3 catheters were collected. Hematocrit remained unchanged during the sampling period. Hormone analysis Plasma cortisol was measured using the radiocompetition assay as previously described (16) and plasma aldosterone using radioimmunoassay (17). The sensitivity of the cortisol assay (0°5 mL plasma sample) was 0.1 ng/mL and that of the aldosterone assay (2 mL plasma sample) was 5 pg/mL. The inter- and intra-assay variations were 5% and 3% respectively, at a mean value of 0.5 ng/tube for cortisol. They were 15% and 10% respectively for aldosterone (400 pg/tube). Expression of results and statistical treatment Hormone levels are presented as mean _ SEM. Differences were evaluated statistically using the Fisher-Student t-test. Hormone hepatic flows are expressed as ng/min/kg body weight calculated as the product of concentration (ng/mL) and blood flow (mL/min/kg bw). RESULTS Nvcthemeral chanoes in plasma corlisol The Fig. 1 demonstrates that the patterns absolutely paralleled in the three vessels. Mean value of the 29 arterial plasma samples (5.92 +0.30 ng/mL) was significantly higher than that of the portal vein (5.12 _ 0.24 ng/mL) and than that of the hepatic vein (4.50 _ 0.21 ng/mL) (respectively +16% and +31%, beth P < 0.05). The difference between portal and hepatic veins was also significant (+14%, P < 0.05). After beth meals (9 AM and 4 PM), plasma cortisol concentrations decreased and then several pic values appeared : 3 between meals and 4 at night.
STEROIDS 5311-2
January-February 1989
52
G a r d y - G o d i l l o t e t al: CALF ALDOSTERONE AND CORTISOL CATABOLISM
mesenteric artery 10
portal vein
i
~-
o
"
.
. •
9"1'1
AM
'
I
•
1 PM
I
3
•
I
'
7
(h)
, Time •
5
I
•
9
I
•
11
I
•
1 AM
I
•
3
'
s
•
•
7
Figure 1. Plasma cortisol levels in mesenteric artery, portal vein and hepatic vein of the calf. (Meals: 9 AM and 4 PM).
I oo ~" 80 J~ O')
60 E
=~ 40 ~ 2o x:~ .~_
0
~Qe-. -20 o
-~- -40 o (5 -60 8 ~ ~mmou ~ a; ,3 ~; ~
1 2 3 mmm " ~ ,'~", . . ~ . O3
AM
PM
m6
8
10
12
2
4
6
8
tO
AM
Figure 2. Cortisol hepatic balance evolution over 24 h. (Meals: 9 A M and 4 PM).
STEROIDS 53/1-2
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Gardy-Godillot et al: CALF ALDOSTERONE AND CORTISOL CATABOLISM
53
Hepatic b~llance for plasma cortis01 (Fie. 2} Meals were followed by decreasing blood flow in the portal vein (-12% after the morning meal and -7% after the afternoon meal). Increased flow in the hepatic artery immediately after meals contrasted with the value observed in the portal vein. The total hepatic blood flow (portal vein flow + hepatic artery flow) did not vary significantly with the meals. The hepatic balance of cortisol expressed as the difference between the uptake of cortisol by the liver and the subsequent release of cortisol from it permits us to estimate the role of the liver in the catabolism of cortisol : [artery flow x arterial cortisol level + portal flow x portal cortisol level] - [hepatic flow (artery + portal flow) x hepatic vein cortisol level]. We demonstrated the following pattern (Fig. 2) for diurnal changes in cortisol hepatic balance. Between meals, changes in hepatic balance for cortisol paralleled the pattern of cortisol concentrations, except just after the morning meal, when an increased catabolism coincided with a decreased level. After the 4 PM meal, the hepatic balance of cortisol decreased and became negative at 5.15 PM. After that, it increased regularly until 1 AM
(from
-35 ng/min/kg bw to +55ng/min/kg bw). Then, cortis01 metabolism paralleled the changes observed for the concentrations, with a drop until 3 AM and then a peak value at 5 AM.
Both characteristic values were significantly different
(between 3 AM and 5 AM, +250%, P < 0.05) and the value at significantly lower than that at t AM (-60%, P < 0.05).
STEROIDS 53/1-2
January-February 1989
3 AM was
54
Gardy-Godillot et al: CALF ALDOSTERONE AND CORTISOL CATABOLISM
The mean hepatic balance of cortisol over 24 h indicated a total catabolism of 61 ~g/24 h/kg bw representing 13% of the cortisol entering into the liver.
Chanoes in plasma aldosterone levels for the 24 h of the dav lFia. 3/ After the morning meal, plasma aldosterone levels sharply increased until 10:30 AM (+88%, P < 0.05), after which changes were not significant. Levels observed in the mesenteric artery were always higher than in the veins, and the daily mean of the arterial level was significantly higher than in the portal vein (+38%, P < 0.05) and the hepatic vein (+30%,
P < 0,05).
50 ._1
E ~"
8~
a mesenteric artery • portal.vein.
40
v
30 O
~ 2o E
10
Time (h) 0
9 11 1 3 AM PM
5 7
9 11 1 3 AM
Fiaure 3. Plasma aldosterone levels in mesenteric hepatic vein. (Meals: 9 AM and 4 PM).
5
7
artery, portal vein, and
Pattern of heoatic balance for aldosterone (Fla. 4/ Although the hepatic balance of aldosterone indicated a total catabolism of 231 ng/24 h/kg bw~ ~
the 24 h, 2 contrasting periods could be distinguished :
between both meals, aldosterone was primarily catabolised in the liver and then, at night the negative balance of aldosterone would rather suggest a production of aldosterone by the liver.
STEROIDS 53/1-2
January-February 1989
Gardy-Godillot et al: CALF ALDOSTERONE AND CORTISOL CATABOLISM
..Q
350
E
250
v
55
150
O t-
5o ..Q
.o Q.
-50
t-e..
-150
o
Time (h)
-250 -r--/ O
-o
9
AM
O
o~
O
co
O
o
O
co
O
co
7
O
~
O
o~
PM
O
o~
O
o~
O
C~
eo .~.
AM
Fiaure 4. Aldosterone hepatic balance evolution over 24h (Meals: 9 AM and 4 PM).
DISCUSSION Using the conscious calf bearing indwelling catheters and electromagnetic blood flow
probes,
we
have demonstrated
the
relative parts
played
by the
gastrointestinal tract and the liver in the catabolism of plasma cortisol and aldosterone. Thus, the steroid levels are lower in the portal vein than in the arteries, indicating that a significant part of steroid catabolism occured in the intestine. There is only a small body of experimental evidence in the literature that cortisol metabolism occurs substantially in organs other than the liver. That has been demonstrated in the dog (4) and in the sheep (9).
STEROIDS 53/3-2
January-February 1989
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Gardy-Godillot et al: CALF ALDOSTERONE AND CORTISOL CATABOLISM
Experiments in our laboratory on the anesthetized guinea pig have demonstrated that the contribution of different organs to the catabolism of cortisol were 2% for adrenals, 10% for kidneys (18),
and 25% for the splanchnic area (19).
Confirming earlier observations of Lien e t a l (20)in the dog and monkey concerning the role played by the liver in the metabolism of cortisol, the irreversible transformation into tetrahydro compounds was concomitant with a conversion of cortisone into cortisol as demonstrated in the guinea pig (19,21) and in man (22). In our study over 24 h, the cortisol balance of the calf liver indicated a catabolism which varied with plasma concentrations between meals and then increased in the evening and at night with a peak value at 5 AM. The observation of the varying concentrations of plasma cortisol in the artery, the portal vein, and the hepatic vein indicates a catabolism of 13.5% of the cortisol reaching the intestine which is quantitatively as important as that occurring in the liver. These values, as evaluated over 24 h, probably reflect more precise measurements than those obtained by others with one sample per day or with in vitro experiments. Comparison between aldosterone and cortisol catabolism as measured by the hepatic balance and the percentage of concentration between mesenteric artery and portal vein indicated that aldosterone was more catabolized than cortisol in the splanchnic area. The intestine catabolism of aldosterone was two-fold higher than that of cortisol. The same difference could be reported at the hepatic level. Studies on plasma disappearance of [3H]aldosterone (23) have shown the high hepatic clearance of aldosterone. Furthermore, the slight plasma binding of these hormone to albumin (24, 25) explained the difference with cortisol for the catabolism.
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Cardy-Codillot et ah CALF ALDOSTERONE AND CORTISOL CATABOLISM
57
Indeed it i's well known that corUsol is specifically bound to a corticosteroidbinding globulin (CBG) which protects the hormone and diminishes its catabolism (26). In conclusion, using the calf as a model, with measurements of hepatic balance and hormone concentrations over 24 h,
we demonstrated that cortisol and
aldosterone were catabolized in the intestine as intensively as in the liver. These results contrast with numerous reports which have indicated a predominant role for the liver. AC,K N O W ~ E N T S The authors thank D. Episse for her skillful technical assistance. REFERENCES 1. Yates FE, and Urquhart J (1962). Control of plasma concentrations of adrenocortical hormones. PHYSIOL REV 42: 359-443. 2. Jenkins J S (1966). The metabolism of cortisol by human extra-hepatic tissues. J ENDOCRINOL 34: 51-56. 3. Reach G, Nakane H, Nakane Y, Auzan C, and Corvol P (1977). Cortisol metabolism and excretion in the isolated perfused rat kidney. STEROIDS 30: 621 -635. 4. McCormick J R, Herman A H, Lien W M, and Egdahl R H (1974). Hydrocortisone metabolism in the adrenalectomized dog : the quantitative significance of each organ system in the total metabolic clearance of hydrocortisone. ENDOCRINOLOGY 94: 17-26. 5. Sowell J G, Hagen A A, and Troop R C (1971). Metabolism of cortisone 4-14C by rat lung tissue. STEROIDS 18: 289-301. 6. Koerner D R (1966). 111~-hydroxysteroid deshydrogenase of lung and testis. ENDOCRINOLOGY 79: 935-938. 7. Yudaev N A, and Filonova E A (1966). Effect of androsterone on the conversion of hydroxycorticosterone into cortisone in guinea-pig tissues in vitro. FED PROC TRANS ~JDJ3J,..Z~,T69. 8. Nienstedt W, and Harri M P (1979). Intestinal absorption and metabolism of 17-hydroxyprogesterone, deoxycorticosterone and cortisol in the dog. J STEROID BIOCHEM 11: 1209-1215. 9. Paterson J Y F, and Harrison F A (1972). The splanchnic and hepatic uptake of cortisol in conscious and anaesthetized sheep. J ENDOCRINOL 55: 335-350. 10. Panaretto B A, Paterson J Y F, and Hills F (1973). The relationship of the splanchnic, hepatic and renal clearance rates to the metabolic clearance rate of cortisol in conscious sheep. J ENDOCRINOL 56" 285-294.
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January-February 1989
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Gardy-Godiliot eta[: CALF ALDOSTFRON[ AND COR~ !SOL CA-A!~'O!_iSM
11. Baird G D, Symonds H W, and Ash R (1975). Some observations on metab,olite production and utilization in vivo by the gut and liver of adult dairy cows. J AGRIC SCI 85: 281-296. 12. Carr S B, and Jacobson D R (1968). Method for measurement of gastrointestinal absorption in normal animals, combining portal-carotid differences and telemetered portal flow by Doppler shift. J DAIRY SCI 51: 721-729. 13. Brockman R P, and Bergman E N (1975). Quantitative aspect of insulin secretion and its hepatic and renal removal in sheep. AM J PHYSIOL 5: 1338-1343. 1 4. Katz M L, and Bergman E N (1969). Simultaneous measurements of hepatic and portal venous blood flow in the sheep and dog. AM J PHYSIOL 216: 946-952. 15. Durand D, Bauchart D, Lefaivre J, and Donnat J P(1988). Method for continuous measurement of blood metabolite hepatic balance in conscious preruminant calves. J. DAIRY SCI (in press). 16. Dalle M, and Delost P (1976). Plasma and adrenal cortisol concentrations in fetal, newborn and mother guinea-pigs during the perinatal period. J ENDOCRINOL 70" 207-214. 1 7. Giry J, and Delost P (1977). Changes in the concentrations of aidosterone in the plasma and adrenal glands of the foetus, the newborn and the pregnant guinea-pig during the perinatal period. ACTA ENDOCRINOL 84: 133-141. 18. Manin M (1984). Etude dynamique du m6tabolisme p~riph~rique des glucocortico'fdes chez le Cobaye. Th~se de Doctorat ~s Sciences Naturelles (1984). 19. Manin M, Tournaire C, and Delost P (1983). The splanchnic removal of cortisol from plasma of anaesthetized adult guinea-pigs. J ENDOCRINOL 96: 273-280. 20. Lien W M, Mc Cormick J R, Davies M W, and Egdahl R H (1970). Corticosteroid clearance by the gastrointestinal tract in dogs and monkey. ENDOCRINOLOGY 87: 206-208. 21. Pasqualini J R, Costa Naeves S, Ito Y, and Nguyen B L (1970). Reciprocal cortisol-cortisone conversions in the total tissue and subcellular fractions of foetal and adult guinea-pig liver. J STEROID BIOCHEM 1: 341-347. 22. Murphy B E P (1981). Ontogeny of cortisol-cortisone interconversion in human tissues : a role for cortisone in human fetal development: J STEROID BIOCHEM 14: 811-817. 23. Schneider B G, Davis J O, Baumber J S, and Johnson J A (1970). The hepatic metabolism of renin and aldosterone. CIRCULATION RESEARCH Suppl. I, Vol. XXVl and XXVlI, 1-175-1-183. 24. Tait J F, Burstein S (1964). In vivo studies of steroid dynamics in man. In: The Hormones ( Pincus G, Thiman K V and Astwood E B, eds), Vol. 5, Academic Press, New York , pp 441-557. 25. Giry J, and Delost P (1980). S6crdtion, mdtabolisme et transport de I'aldost~rone dans la p~riode n~onatale chez le Cobaye. REPROD. NUTR. DEV 20: 271 -276. 26. Dalle M, and Delost P (1980). Maturation of glucocorticoid activity in the fetal guinea-pig during the end of gestation. REPROD. NUTR. DEV 20: 277-286.
STEROIDS 53]1-2
January-February 1989
P. Delost. •Laboratoire de Physiologie Animale et UA CNRS 1123, Universit~ Blaise Pascal-Clermont-Ferrand II, Ensemble Scientifique des C~zeaux, B.P. 45, 63170 AubiEre, France; bI.N.R.A. Theix/Clermont-Ferrand,63122 Ceyrat, France Correspondingauthor: M. Dalle ReceivedJanuary 6, 1988 RevisedMay 10, 1988
ABSTRACT Intestinal and hepatic catabolism of cortisol and aldosterone were studied in the calf using blood samples from the mesenteric artery and portal and hepatic veins collected over 24 h, the hepatic blood flow being continuously recorded during this period. The total hepatic blood flow remained broadly constant over the 24 h~ a].t~cu~ meals were followed by decreasing flow in the portal vein and by increasing flow in the hepatic artery. The intestinal tract catabolizes cortisol as intensively as the liver (both 13% of cortisol reaching the organ). The part played by the gut and the liver in the catabolism of aldosterone were also equivalent (both 30% of aldosterone reaching the organ). This 24-h study demonstrated that a constant ratio existed between secretion and catabolism of cortisol while the hepatic balance of aldosterone seemed to be modified during the night. INTRODUCTION Although the liver is usually accepted as being the major site for the metabolism of cortisol (1), there is evidence that other tissues are able to change the structure of steroids. Cortisone was the major metabolite produced by all the experimental tissues, in vivo and in vitro. The kidney may be an important site for the metabolism of cortisol by oxidation to cortisone (2,3); however, the relative metabolic clearance rate of the kidney for cortisol remained much lower than that of the liver and the gastrointestinal tract (4). The lung has been implicated in the metabolism of steroid hormones (5) and the presence of 118hydroxysteroid dehydrogenase activity has been reported in the lungs of rats and
STEROI DS 53/1-2
January-February 1989 (49-58)
49
50
Gardy-Godillot et al: CALF ALDOSTERONE AND CORTISOL CATABOLISM
guinea pigs (6,7). However, demonstration of the pulmonary metabolism of ~ cortisol in vivo has not yet been achieved. The intestinal metabolism of cortisol has also been demonstrated in the dog (8). Nevertheless, all these studies could not be easily translated to the physiological event occurring in the conscious animal. An approach to the problem of the cortisol metabolism in the conscious animal has been described in the sheep (9,10) with the measurement of cortisol dynamics after radioactive cortisol infusion. Metabolic balance studies involving the combined measurements of venous-arterial concentration differences and blood flows have been tried on dairy cows (11) and preruminant calves (12) and sheep (13,14). As intermittent values of blood flow gave only
a general idea of the
function of an organ, we have undertaken to sample blood regularly from the mesenteric artery and the portal and the hepatic veins to measure the cortisol levels over 24 h, paralleling a continuous recording of the hepatic blood flow using the preruminant calf as a model (15). Thus, we have investigated daily cortisol metabolism in the gastrointestinal tract in relation to the hepatic balance of cortisol and aldosterone. To our knowledge, no investigation of daily aldosterone metabolism and hepatic flows has previously been undertaken.
MATERIALSAND METHODS Animals The study was carried out on five 2-week-old Friesian-Holstein male calves weighing 45 + 3 kg. They were fed a milk substitute containing 22.5% tallow and 23% protein twice daily. They were bearing indwelling catheters implanted in the portal vein, in a mesenteric artery, and in the hepatic vein. Electromagnetic blood-flow probes were placed around the portal vein and around the most accessible branch of the hepatic artery. Surgery and blood flow measurement were
STEROIDS 53/1-2
January-February 1989
Gardy-Godillot et al: CALF ALDOSTERONE AND CORTISOL CATABOLISM
51
described (t5). Blood flow was calculated from the graphic recorder, Ibe flow probe regression line established before surgery and the conversion factor were determined from variations in packed cell volume. This technic of electromagnetic flowmetry gave results in complete agreement with dye dilution assays. The mean values obtained in 2-week-old calves were similar to those measured in older animals (3- and 5-week-old calves) and remained constant during a 3-weekperiod. During a 24-h period between 8 AM and 8 AM of the following day, 29 3mL-samples of blood from each of the 3 catheters were collected. Hematocrit remained unchanged during the sampling period. Hormone analysis Plasma cortisol was measured using the radiocompetition assay as previously described (16) and plasma aldosterone using radioimmunoassay (17). The sensitivity of the cortisol assay (0°5 mL plasma sample) was 0.1 ng/mL and that of the aldosterone assay (2 mL plasma sample) was 5 pg/mL. The inter- and intra-assay variations were 5% and 3% respectively, at a mean value of 0.5 ng/tube for cortisol. They were 15% and 10% respectively for aldosterone (400 pg/tube). Expression of results and statistical treatment Hormone levels are presented as mean _ SEM. Differences were evaluated statistically using the Fisher-Student t-test. Hormone hepatic flows are expressed as ng/min/kg body weight calculated as the product of concentration (ng/mL) and blood flow (mL/min/kg bw). RESULTS Nvcthemeral chanoes in plasma corlisol The Fig. 1 demonstrates that the patterns absolutely paralleled in the three vessels. Mean value of the 29 arterial plasma samples (5.92 +0.30 ng/mL) was significantly higher than that of the portal vein (5.12 _ 0.24 ng/mL) and than that of the hepatic vein (4.50 _ 0.21 ng/mL) (respectively +16% and +31%, beth P < 0.05). The difference between portal and hepatic veins was also significant (+14%, P < 0.05). After beth meals (9 AM and 4 PM), plasma cortisol concentrations decreased and then several pic values appeared : 3 between meals and 4 at night.
STEROIDS 5311-2
January-February 1989
52
G a r d y - G o d i l l o t e t al: CALF ALDOSTERONE AND CORTISOL CATABOLISM
mesenteric artery 10
portal vein
i
~-
o
"
.
. •
9"1'1
AM
'
I
•
1 PM
I
3
•
I
'
7
(h)
, Time •
5
I
•
9
I
•
11
I
•
1 AM
I
•
3
'
s
•
•
7
Figure 1. Plasma cortisol levels in mesenteric artery, portal vein and hepatic vein of the calf. (Meals: 9 AM and 4 PM).
I oo ~" 80 J~ O')
60 E
=~ 40 ~ 2o x:~ .~_
0
~Qe-. -20 o
-~- -40 o (5 -60 8 ~ ~mmou ~ a; ,3 ~; ~
1 2 3 mmm " ~ ,'~", . . ~ . O3
AM
PM
m6
8
10
12
2
4
6
8
tO
AM
Figure 2. Cortisol hepatic balance evolution over 24 h. (Meals: 9 A M and 4 PM).
STEROIDS 53/1-2
January-February 1989
Gardy-Godillot et al: CALF ALDOSTERONE AND CORTISOL CATABOLISM
53
Hepatic b~llance for plasma cortis01 (Fie. 2} Meals were followed by decreasing blood flow in the portal vein (-12% after the morning meal and -7% after the afternoon meal). Increased flow in the hepatic artery immediately after meals contrasted with the value observed in the portal vein. The total hepatic blood flow (portal vein flow + hepatic artery flow) did not vary significantly with the meals. The hepatic balance of cortisol expressed as the difference between the uptake of cortisol by the liver and the subsequent release of cortisol from it permits us to estimate the role of the liver in the catabolism of cortisol : [artery flow x arterial cortisol level + portal flow x portal cortisol level] - [hepatic flow (artery + portal flow) x hepatic vein cortisol level]. We demonstrated the following pattern (Fig. 2) for diurnal changes in cortisol hepatic balance. Between meals, changes in hepatic balance for cortisol paralleled the pattern of cortisol concentrations, except just after the morning meal, when an increased catabolism coincided with a decreased level. After the 4 PM meal, the hepatic balance of cortisol decreased and became negative at 5.15 PM. After that, it increased regularly until 1 AM
(from
-35 ng/min/kg bw to +55ng/min/kg bw). Then, cortis01 metabolism paralleled the changes observed for the concentrations, with a drop until 3 AM and then a peak value at 5 AM.
Both characteristic values were significantly different
(between 3 AM and 5 AM, +250%, P < 0.05) and the value at significantly lower than that at t AM (-60%, P < 0.05).
STEROIDS 53/1-2
January-February 1989
3 AM was
54
Gardy-Godillot et al: CALF ALDOSTERONE AND CORTISOL CATABOLISM
The mean hepatic balance of cortisol over 24 h indicated a total catabolism of 61 ~g/24 h/kg bw representing 13% of the cortisol entering into the liver.
Chanoes in plasma aldosterone levels for the 24 h of the dav lFia. 3/ After the morning meal, plasma aldosterone levels sharply increased until 10:30 AM (+88%, P < 0.05), after which changes were not significant. Levels observed in the mesenteric artery were always higher than in the veins, and the daily mean of the arterial level was significantly higher than in the portal vein (+38%, P < 0.05) and the hepatic vein (+30%,
P < 0,05).
50 ._1
E ~"
8~
a mesenteric artery • portal.vein.
40
v
30 O
~ 2o E
10
Time (h) 0
9 11 1 3 AM PM
5 7
9 11 1 3 AM
Fiaure 3. Plasma aldosterone levels in mesenteric hepatic vein. (Meals: 9 AM and 4 PM).
5
7
artery, portal vein, and
Pattern of heoatic balance for aldosterone (Fla. 4/ Although the hepatic balance of aldosterone indicated a total catabolism of 231 ng/24 h/kg bw~ ~
the 24 h, 2 contrasting periods could be distinguished :
between both meals, aldosterone was primarily catabolised in the liver and then, at night the negative balance of aldosterone would rather suggest a production of aldosterone by the liver.
STEROIDS 53/1-2
January-February 1989
Gardy-Godillot et al: CALF ALDOSTERONE AND CORTISOL CATABOLISM
..Q
350
E
250
v
55
150
O t-
5o ..Q
.o Q.
-50
t-e..
-150
o
Time (h)
-250 -r--/ O
-o
9
AM
O
o~
O
co
O
o
O
co
O
co
7
O
~
O
o~
PM
O
o~
O
o~
O
C~
eo .~.
AM
Fiaure 4. Aldosterone hepatic balance evolution over 24h (Meals: 9 AM and 4 PM).
DISCUSSION Using the conscious calf bearing indwelling catheters and electromagnetic blood flow
probes,
we
have demonstrated
the
relative parts
played
by the
gastrointestinal tract and the liver in the catabolism of plasma cortisol and aldosterone. Thus, the steroid levels are lower in the portal vein than in the arteries, indicating that a significant part of steroid catabolism occured in the intestine. There is only a small body of experimental evidence in the literature that cortisol metabolism occurs substantially in organs other than the liver. That has been demonstrated in the dog (4) and in the sheep (9).
STEROIDS 53/3-2
January-February 1989
56
Gardy-Godillot et al: CALF ALDOSTERONE AND CORTISOL CATABOLISM
Experiments in our laboratory on the anesthetized guinea pig have demonstrated that the contribution of different organs to the catabolism of cortisol were 2% for adrenals, 10% for kidneys (18),
and 25% for the splanchnic area (19).
Confirming earlier observations of Lien e t a l (20)in the dog and monkey concerning the role played by the liver in the metabolism of cortisol, the irreversible transformation into tetrahydro compounds was concomitant with a conversion of cortisone into cortisol as demonstrated in the guinea pig (19,21) and in man (22). In our study over 24 h, the cortisol balance of the calf liver indicated a catabolism which varied with plasma concentrations between meals and then increased in the evening and at night with a peak value at 5 AM. The observation of the varying concentrations of plasma cortisol in the artery, the portal vein, and the hepatic vein indicates a catabolism of 13.5% of the cortisol reaching the intestine which is quantitatively as important as that occurring in the liver. These values, as evaluated over 24 h, probably reflect more precise measurements than those obtained by others with one sample per day or with in vitro experiments. Comparison between aldosterone and cortisol catabolism as measured by the hepatic balance and the percentage of concentration between mesenteric artery and portal vein indicated that aldosterone was more catabolized than cortisol in the splanchnic area. The intestine catabolism of aldosterone was two-fold higher than that of cortisol. The same difference could be reported at the hepatic level. Studies on plasma disappearance of [3H]aldosterone (23) have shown the high hepatic clearance of aldosterone. Furthermore, the slight plasma binding of these hormone to albumin (24, 25) explained the difference with cortisol for the catabolism.
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Indeed it i's well known that corUsol is specifically bound to a corticosteroidbinding globulin (CBG) which protects the hormone and diminishes its catabolism (26). In conclusion, using the calf as a model, with measurements of hepatic balance and hormone concentrations over 24 h,
we demonstrated that cortisol and
aldosterone were catabolized in the intestine as intensively as in the liver. These results contrast with numerous reports which have indicated a predominant role for the liver. AC,K N O W ~ E N T S The authors thank D. Episse for her skillful technical assistance. REFERENCES 1. Yates FE, and Urquhart J (1962). Control of plasma concentrations of adrenocortical hormones. PHYSIOL REV 42: 359-443. 2. Jenkins J S (1966). The metabolism of cortisol by human extra-hepatic tissues. J ENDOCRINOL 34: 51-56. 3. Reach G, Nakane H, Nakane Y, Auzan C, and Corvol P (1977). Cortisol metabolism and excretion in the isolated perfused rat kidney. STEROIDS 30: 621 -635. 4. McCormick J R, Herman A H, Lien W M, and Egdahl R H (1974). Hydrocortisone metabolism in the adrenalectomized dog : the quantitative significance of each organ system in the total metabolic clearance of hydrocortisone. ENDOCRINOLOGY 94: 17-26. 5. Sowell J G, Hagen A A, and Troop R C (1971). Metabolism of cortisone 4-14C by rat lung tissue. STEROIDS 18: 289-301. 6. Koerner D R (1966). 111~-hydroxysteroid deshydrogenase of lung and testis. ENDOCRINOLOGY 79: 935-938. 7. Yudaev N A, and Filonova E A (1966). Effect of androsterone on the conversion of hydroxycorticosterone into cortisone in guinea-pig tissues in vitro. FED PROC TRANS ~JDJ3J,..Z~,T69. 8. Nienstedt W, and Harri M P (1979). Intestinal absorption and metabolism of 17-hydroxyprogesterone, deoxycorticosterone and cortisol in the dog. J STEROID BIOCHEM 11: 1209-1215. 9. Paterson J Y F, and Harrison F A (1972). The splanchnic and hepatic uptake of cortisol in conscious and anaesthetized sheep. J ENDOCRINOL 55: 335-350. 10. Panaretto B A, Paterson J Y F, and Hills F (1973). The relationship of the splanchnic, hepatic and renal clearance rates to the metabolic clearance rate of cortisol in conscious sheep. J ENDOCRINOL 56" 285-294.
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Gardy-Godiliot eta[: CALF ALDOSTFRON[ AND COR~ !SOL CA-A!~'O!_iSM
11. Baird G D, Symonds H W, and Ash R (1975). Some observations on metab,olite production and utilization in vivo by the gut and liver of adult dairy cows. J AGRIC SCI 85: 281-296. 12. Carr S B, and Jacobson D R (1968). Method for measurement of gastrointestinal absorption in normal animals, combining portal-carotid differences and telemetered portal flow by Doppler shift. J DAIRY SCI 51: 721-729. 13. Brockman R P, and Bergman E N (1975). Quantitative aspect of insulin secretion and its hepatic and renal removal in sheep. AM J PHYSIOL 5: 1338-1343. 1 4. Katz M L, and Bergman E N (1969). Simultaneous measurements of hepatic and portal venous blood flow in the sheep and dog. AM J PHYSIOL 216: 946-952. 15. Durand D, Bauchart D, Lefaivre J, and Donnat J P(1988). Method for continuous measurement of blood metabolite hepatic balance in conscious preruminant calves. J. DAIRY SCI (in press). 16. Dalle M, and Delost P (1976). Plasma and adrenal cortisol concentrations in fetal, newborn and mother guinea-pigs during the perinatal period. J ENDOCRINOL 70" 207-214. 1 7. Giry J, and Delost P (1977). Changes in the concentrations of aidosterone in the plasma and adrenal glands of the foetus, the newborn and the pregnant guinea-pig during the perinatal period. ACTA ENDOCRINOL 84: 133-141. 18. Manin M (1984). Etude dynamique du m6tabolisme p~riph~rique des glucocortico'fdes chez le Cobaye. Th~se de Doctorat ~s Sciences Naturelles (1984). 19. Manin M, Tournaire C, and Delost P (1983). The splanchnic removal of cortisol from plasma of anaesthetized adult guinea-pigs. J ENDOCRINOL 96: 273-280. 20. Lien W M, Mc Cormick J R, Davies M W, and Egdahl R H (1970). Corticosteroid clearance by the gastrointestinal tract in dogs and monkey. ENDOCRINOLOGY 87: 206-208. 21. Pasqualini J R, Costa Naeves S, Ito Y, and Nguyen B L (1970). Reciprocal cortisol-cortisone conversions in the total tissue and subcellular fractions of foetal and adult guinea-pig liver. J STEROID BIOCHEM 1: 341-347. 22. Murphy B E P (1981). Ontogeny of cortisol-cortisone interconversion in human tissues : a role for cortisone in human fetal development: J STEROID BIOCHEM 14: 811-817. 23. Schneider B G, Davis J O, Baumber J S, and Johnson J A (1970). The hepatic metabolism of renin and aldosterone. CIRCULATION RESEARCH Suppl. I, Vol. XXVl and XXVlI, 1-175-1-183. 24. Tait J F, Burstein S (1964). In vivo studies of steroid dynamics in man. In: The Hormones ( Pincus G, Thiman K V and Astwood E B, eds), Vol. 5, Academic Press, New York , pp 441-557. 25. Giry J, and Delost P (1980). S6crdtion, mdtabolisme et transport de I'aldost~rone dans la p~riode n~onatale chez le Cobaye. REPROD. NUTR. DEV 20: 271 -276. 26. Dalle M, and Delost P (1980). Maturation of glucocorticoid activity in the fetal guinea-pig during the end of gestation. REPROD. NUTR. DEV 20: 277-286.
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