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Age changes in the level of serum immunoreactive insulin in three strains of rats
Lüe Sciences Vol . 10, Part I, pp . 105-109, 1971 .. Printed in Great Britain
Pergamon Press
Ilf TH$ LßVBL OF BSRlA! IMMUIFDREACTIY$ LfSiJLIIf IIf TH1tBB STRAIHS OF RATS
AG$ CEAFGEB
Carolya D. Berdanier, ~y iI . Marshall aad Phylis Moser Hueaa Nutrition Research Dirtsion, Agricultural Research Service, United States Department of Agriculture, Heltaville, Maryland 20705 (Received 10 November 1970; in final form SO November 1970) Strain differences in response to changes in the type of dietary esrbobydrate bare been reported previously by this laboratory (1-6) . These differences bare been observed u changes in the activities of several key ansymea is the carbohydrate sietabolic pst}nregs as well u changes is the lipid content of the blood, liver, . and camas .
Other
investigtitors (7,8) bare noted atraia differences is the activities of several key glycol~rtic ensyaes .
Additional reports bare described
iadiriflnal straiaa of anis~ with obese teadenoies and/or lipid abaoa~aalities (9-12) .
It hu been observed in rats sad 1sv.ans that
hyperiasnliass~.ta l~equent],p sccas~paniea the geaetical~ determined obesity charaateriatic (13-15) .
Since the HRâ l sad inbred ~ strains
bare greater ssauats of carcua sad liver fat thaa . the üi.star strain with carbohydrate feeding, the current studios ware nadertatusa in an sttasipt to define the changes in eer~a issnmoreactivs iasnlin (IRI) with age is these three strains of rata .
If the activities of the carbohydrate
aetsbolisiag easymea are responsive to the level of IRI, then age changes
1Strain of rat developed by these laboratories resulting from a cross of the Peaaaylvaaia State College strain and the Yale (also called the Oaborn-Mendel) strain . This strain has bean described preciously (1) . 23train of rat previously described (16) which is the product of intensive inbreeding of the HHE strain .
105
108
Effect a~ï Age on Insulin Levels
Vol . 10, No. 2
is the level of this bosons could ezplaia the observed differences in carbohydrate aetabolisn . éine groups of sale animals free the üistar3 , HHE and inbred BH$ (IB-BHE) strains were aaiataiaed on a caso.ercial pelletad ration sad were fasted overnight (16 hours) prior to seapliag .
At 50, 100, and
300 deyr of age the animals were aaesthesiaed by as intrsperitoaeal injection of 60 aB/]cg of sodinn saobarbital sad blood withdraam by heart puncture . iastion (lÎ) .
phole blood glucose vas deterained after deproteinSerum isauaoreactive insulin vas deterainefl by the
isuaoreactive teahaigne of Hales and Rendle (18) .
After the blood
vas dynes the animals were killed and the carcsases exmined for signs of gross abnarnalities .
The results are snmaari :ed is Table l .
At 50 days of age BHE sad Iit-HHS animals appeared to be hprperiasulinemic .
The spread of values for these two groups vas
fs3r],y large indicating greater variability within these strains ss cospared to the Wistar strain .
Values for the HHS animals ranged Eras
î6 to 130 Waits/al serum with a uaifara spread throughout this range . Although the Ill-HH8 animals had ae great a range as the H~ animals, east of the insulin values fell near the average value of 15k Waits/al . This sverege great],T exoaeded values observed in ifistar animals at this ege or later in life .
>~r 100 days of age the IAI levels of both the BHB
and IN-HSE animals had dropped considerably .
The Wistar values were
slightly higher at this age than they were at 50 days of age.
Hy
300 days only slight strain differences in IRI were apparent .
However, by
300 deys of age the IH-BHE animals appeared to be mildly hyperglyceaic
3Specific pathogen free üistar rats obtained from Manor Research Fares, Ralston Purina Ccapaigr. hPurina Laboratory Chow, Ralston Purina Caspany.
Vol . 10, No. 2
E17ect ad Age on Insulin Levels
107
TAHLL 1 $ifeet of age aad strata on the fasting lerel of blood glucose and serua i~uaareactire insulin is rats ~~ Arerage huâoréaet ré iAwl~ ô3oôd 8traia veight inanlin glncosa pnaits/sl aerne aB/100 al g 50 dairs of age üiatar
140 (12)1
15 + 12'3
83 + 23
H8B
1T3 (l0)
99 + q3 .
90 + 4
II~-Ba8
175 (l0)
15b + 93
94 +
5
itistar
308 (12)
23 + 33
85 +
2
BRS
325 (12)
42 ± ~
90 ± 8
~-EeE
368 ( 9)
31 + 63
88 +
494 (10)
39 + 2
108 + 7
490 (12)
45 + 3.
l00 +
506 (12)
26 + 33
140 t 153
100 da~!s of sge
8
300 dass of ags üistar I1f-HHS
8
-Huaber of aaimals 28taadard error of the ~eaaa 3This relue is sigaificaat],,T different frac those of the other tw groups at this age (P< .05) as tested b7 Duacaa's aultiple mage test,
108
Effect of Age on Insulin Levels
Vol. 10, No. 2
indicating that the insulin of these saieals may have been inactianal],y deficient .
The pattern of insulin changes with age, however, also
suggests that these animals msy be relatively insensitive to their own insulin with respect to glucose transport.
Thus the early hyperinsnliaesia
~ay represent a ccepensatory aechanise to avercoee this insensitivity ; by 300 days of age these aaisals ee~y be unable to produce as much insulin and symptces reseebling diabetes say be observed . The gnestioa now arises as to what effect this early byperiasuliaemia has oa metabolise .
Several vor]cers have shorn that insulin is important
in either the activation or synthesis of hezokinase (19,20) .
Insulin
has also bees shown to enhance fatty acid synthesis (21,22) .
It is
possible, therefore, that early excess insulin sir serve to increase the synthesis of several ensymss ieporta~ in the regulation of intermediary setabolism .
Dace the eaahiaery for the synthesis of these
ensyees is operational, it is possible that it may no longer be insulin dependent.
Sarlier studies on the time course of insulin response and
the overshoot of ensyee setivity and liver lipid using the starve-refeed technique appear to support this suggestion (23) .
Thus, it is possible
that the strain differences in carbohydrate eetabolise and lipid synthesis msy bs related to age changes in insulin production and activity . Refareaces 1.
M, x. MARKHALL sad R. E. BILDSBFtA1fD, J . Eutr . ~, 227 (1963) .
2.
M. ADAMS, t1SDA Hose Scoaceics Res. Report /24, IIBDA, üashingtaa, D. C. (1964) .
3.
D. D. TAYLOR, S. s . CO11ifAY, S. M. BCHIJSTER, aad M. ADAà~. 21, 275 (19x7) .
à.
M . L. CHASG, S. M . sCHUBT~t, J . A . LEB, C. SdODORA88, aad D . A . BBi1TOlf, J. llutr . ~6, 3xe (19x8> .
5.
M . W. MAR8HJILL, B. P. SMITH, and R. P. LSH!lAälf, Pros . Soc. Szp. Biol . sad Mad. 21, 1271 (1969) .
6.
M . L. CHAEO, J. A. LEB, S. M, sCRU~f~i, ead D. L. TROiPP, J . llutr . (1970), (Ia Press) .
J, llutr.
Vol . 30, No . 2
Effect ad Age on Insulin Levels
109
T.
L. Y. EOGLESt'OK and H. A, xR8H8, Biochsn. J . 114, 8TT (1969) .
8.
A. E. BEBDER tad P. Y. THAIiDAIiI, lfutr. !letab . 12, 22 (1970) .
9.
T. F. ZUClD~t a~ L. M. ZUCIO3R, Proc . Soc. Er~l. Biol . lâed . 110. 16 5 (1962) .
-
10 .
v . v. COLS and B. x . HARKED, Endocrlaolo~+ 23, 318 (1938) .
11 .
J. IüYER, Kutr . Abst . Ra~. ~, 597 (1955) .
12 .
P. LSKZ and A. I . FLEISCiBfAB, Lipids 4, 384 (1969) .
13 .
L. M. ZUCxER and H. K. AlITO11IADE8, Fed. Proc . 2~, 379 (1970) .
14 .
s . M. OERItl'H, Bodocrlaolo~ . 8 4
15 .
c, c~ouvsRAias and P. A. ~TE, Matab. 18, 998 (1969) .
16 .
M. W. ~tetrar+err.~ p, K, A. DURAIID, and M. ADAMB, Proc . 4th Intern . 8rmposita oa Defining tha Lab. Aalmal, ilashiagtoa, D. C., April, 1969 (Ia Press) .
17 .
A. SAIFSit and 8. GERHTBit1~.D, J. Lab. C1ia . Med. ~, 448 (1958) .
18 .
C. K. HALER and P. J. RA®LS, Biochea. J . 8B, 137 (1963) .
19 .
R. J. HANSOlf, S. J. PILxIS, and M. E. xRAiII.; Endocriaolo~ 86, ST
20 .
Y. 8. IL'IIf, Sndokriaol i Goraonoter 1 translated is Fed. Pros . 2~, g7.03
21 .
s . ROUE, F. HO1fIBI, and L. AUBRY, FEHS Lett . ~, 351 (1969) .
22 .
S. M. LEITES and K. x . DAYTYAK, Yoproet !leditsenskoi xhiaü 11,
23 .
B. szEPESI ana c . D. sEHDAKt~, Fed. Pros . 22, 569 (19TO) .
386 (1969) .
(19To) .
-.
.
12, 54 (1966) as
49 (1965) .
Pergamon Press
Ilf TH$ LßVBL OF BSRlA! IMMUIFDREACTIY$ LfSiJLIIf IIf TH1tBB STRAIHS OF RATS
AG$ CEAFGEB
Carolya D. Berdanier, ~y iI . Marshall aad Phylis Moser Hueaa Nutrition Research Dirtsion, Agricultural Research Service, United States Department of Agriculture, Heltaville, Maryland 20705 (Received 10 November 1970; in final form SO November 1970) Strain differences in response to changes in the type of dietary esrbobydrate bare been reported previously by this laboratory (1-6) . These differences bare been observed u changes in the activities of several key ansymea is the carbohydrate sietabolic pst}nregs as well u changes is the lipid content of the blood, liver, . and camas .
Other
investigtitors (7,8) bare noted atraia differences is the activities of several key glycol~rtic ensyaes .
Additional reports bare described
iadiriflnal straiaa of anis~ with obese teadenoies and/or lipid abaoa~aalities (9-12) .
It hu been observed in rats sad 1sv.ans that
hyperiasnliass~.ta l~equent],p sccas~paniea the geaetical~ determined obesity charaateriatic (13-15) .
Since the HRâ l sad inbred ~ strains
bare greater ssauats of carcua sad liver fat thaa . the üi.star strain with carbohydrate feeding, the current studios ware nadertatusa in an sttasipt to define the changes in eer~a issnmoreactivs iasnlin (IRI) with age is these three strains of rata .
If the activities of the carbohydrate
aetsbolisiag easymea are responsive to the level of IRI, then age changes
1Strain of rat developed by these laboratories resulting from a cross of the Peaaaylvaaia State College strain and the Yale (also called the Oaborn-Mendel) strain . This strain has bean described preciously (1) . 23train of rat previously described (16) which is the product of intensive inbreeding of the HHE strain .
105
108
Effect a~ï Age on Insulin Levels
Vol . 10, No. 2
is the level of this bosons could ezplaia the observed differences in carbohydrate aetabolisn . éine groups of sale animals free the üistar3 , HHE and inbred BH$ (IB-BHE) strains were aaiataiaed on a caso.ercial pelletad ration sad were fasted overnight (16 hours) prior to seapliag .
At 50, 100, and
300 deyr of age the animals were aaesthesiaed by as intrsperitoaeal injection of 60 aB/]cg of sodinn saobarbital sad blood withdraam by heart puncture . iastion (lÎ) .
phole blood glucose vas deterained after deproteinSerum isauaoreactive insulin vas deterainefl by the
isuaoreactive teahaigne of Hales and Rendle (18) .
After the blood
vas dynes the animals were killed and the carcsases exmined for signs of gross abnarnalities .
The results are snmaari :ed is Table l .
At 50 days of age BHE sad Iit-HHS animals appeared to be hprperiasulinemic .
The spread of values for these two groups vas
fs3r],y large indicating greater variability within these strains ss cospared to the Wistar strain .
Values for the HHS animals ranged Eras
î6 to 130 Waits/al serum with a uaifara spread throughout this range . Although the Ill-HH8 animals had ae great a range as the H~ animals, east of the insulin values fell near the average value of 15k Waits/al . This sverege great],T exoaeded values observed in ifistar animals at this ege or later in life .
>~r 100 days of age the IAI levels of both the BHB
and IN-HSE animals had dropped considerably .
The Wistar values were
slightly higher at this age than they were at 50 days of age.
Hy
300 days only slight strain differences in IRI were apparent .
However, by
300 deys of age the IH-BHE animals appeared to be mildly hyperglyceaic
3Specific pathogen free üistar rats obtained from Manor Research Fares, Ralston Purina Ccapaigr. hPurina Laboratory Chow, Ralston Purina Caspany.
Vol . 10, No. 2
E17ect ad Age on Insulin Levels
107
TAHLL 1 $ifeet of age aad strata on the fasting lerel of blood glucose and serua i~uaareactire insulin is rats ~~ Arerage huâoréaet ré iAwl~ ô3oôd 8traia veight inanlin glncosa pnaits/sl aerne aB/100 al g 50 dairs of age üiatar
140 (12)1
15 + 12'3
83 + 23
H8B
1T3 (l0)
99 + q3 .
90 + 4
II~-Ba8
175 (l0)
15b + 93
94 +
5
itistar
308 (12)
23 + 33
85 +
2
BRS
325 (12)
42 ± ~
90 ± 8
~-EeE
368 ( 9)
31 + 63
88 +
494 (10)
39 + 2
108 + 7
490 (12)
45 + 3.
l00 +
506 (12)
26 + 33
140 t 153
100 da~!s of sge
8
300 dass of ags üistar I1f-HHS
8
-Huaber of aaimals 28taadard error of the ~eaaa 3This relue is sigaificaat],,T different frac those of the other tw groups at this age (P< .05) as tested b7 Duacaa's aultiple mage test,
108
Effect of Age on Insulin Levels
Vol. 10, No. 2
indicating that the insulin of these saieals may have been inactianal],y deficient .
The pattern of insulin changes with age, however, also
suggests that these animals msy be relatively insensitive to their own insulin with respect to glucose transport.
Thus the early hyperinsnliaesia
~ay represent a ccepensatory aechanise to avercoee this insensitivity ; by 300 days of age these aaisals ee~y be unable to produce as much insulin and symptces reseebling diabetes say be observed . The gnestioa now arises as to what effect this early byperiasuliaemia has oa metabolise .
Several vor]cers have shorn that insulin is important
in either the activation or synthesis of hezokinase (19,20) .
Insulin
has also bees shown to enhance fatty acid synthesis (21,22) .
It is
possible, therefore, that early excess insulin sir serve to increase the synthesis of several ensymss ieporta~ in the regulation of intermediary setabolism .
Dace the eaahiaery for the synthesis of these
ensyees is operational, it is possible that it may no longer be insulin dependent.
Sarlier studies on the time course of insulin response and
the overshoot of ensyee setivity and liver lipid using the starve-refeed technique appear to support this suggestion (23) .
Thus, it is possible
that the strain differences in carbohydrate eetabolise and lipid synthesis msy bs related to age changes in insulin production and activity . Refareaces 1.
M, x. MARKHALL sad R. E. BILDSBFtA1fD, J . Eutr . ~, 227 (1963) .
2.
M. ADAMS, t1SDA Hose Scoaceics Res. Report /24, IIBDA, üashingtaa, D. C. (1964) .
3.
D. D. TAYLOR, S. s . CO11ifAY, S. M. BCHIJSTER, aad M. ADAà~. 21, 275 (19x7) .
à.
M . L. CHASG, S. M . sCHUBT~t, J . A . LEB, C. SdODORA88, aad D . A . BBi1TOlf, J. llutr . ~6, 3xe (19x8> .
5.
M . W. MAR8HJILL, B. P. SMITH, and R. P. LSH!lAälf, Pros . Soc. Szp. Biol . sad Mad. 21, 1271 (1969) .
6.
M . L. CHAEO, J. A. LEB, S. M, sCRU~f~i, ead D. L. TROiPP, J . llutr . (1970), (Ia Press) .
J, llutr.
Vol . 30, No . 2
Effect ad Age on Insulin Levels
109
T.
L. Y. EOGLESt'OK and H. A, xR8H8, Biochsn. J . 114, 8TT (1969) .
8.
A. E. BEBDER tad P. Y. THAIiDAIiI, lfutr. !letab . 12, 22 (1970) .
9.
T. F. ZUClD~t a~ L. M. ZUCIO3R, Proc . Soc. Er~l. Biol . lâed . 110. 16 5 (1962) .
-
10 .
v . v. COLS and B. x . HARKED, Endocrlaolo~+ 23, 318 (1938) .
11 .
J. IüYER, Kutr . Abst . Ra~. ~, 597 (1955) .
12 .
P. LSKZ and A. I . FLEISCiBfAB, Lipids 4, 384 (1969) .
13 .
L. M. ZUCxER and H. K. AlITO11IADE8, Fed. Proc . 2~, 379 (1970) .
14 .
s . M. OERItl'H, Bodocrlaolo~ . 8 4
15 .
c, c~ouvsRAias and P. A. ~TE, Matab. 18, 998 (1969) .
16 .
M. W. ~tetrar+err.~ p, K, A. DURAIID, and M. ADAMB, Proc . 4th Intern . 8rmposita oa Defining tha Lab. Aalmal, ilashiagtoa, D. C., April, 1969 (Ia Press) .
17 .
A. SAIFSit and 8. GERHTBit1~.D, J. Lab. C1ia . Med. ~, 448 (1958) .
18 .
C. K. HALER and P. J. RA®LS, Biochea. J . 8B, 137 (1963) .
19 .
R. J. HANSOlf, S. J. PILxIS, and M. E. xRAiII.; Endocriaolo~ 86, ST
20 .
Y. 8. IL'IIf, Sndokriaol i Goraonoter 1 translated is Fed. Pros . 2~, g7.03
21 .
s . ROUE, F. HO1fIBI, and L. AUBRY, FEHS Lett . ~, 351 (1969) .
22 .
S. M. LEITES and K. x . DAYTYAK, Yoproet !leditsenskoi xhiaü 11,
23 .
B. szEPESI ana c . D. sEHDAKt~, Fed. Pros . 22, 569 (19TO) .
386 (1969) .
(19To) .
-.
.
12, 54 (1966) as
49 (1965) .