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The effects of CoCl2 on glucagon levels in plasma and pancreas of the rat
The Effects of CoCl, on Glucagon Levels in Plasma and Pancreas of the Rat By J. DEV. LOCHNER, A. M. EISENTRAUTAND R. H. UNGER Fed, male adult rats were given an i.p. injection of CoCl, (25 mg./Kg.) after pretreatment with nicotinamide (750 mg./Kg.) to reduce the mortality rate. A transient hyperglycemic phase was observed during the first hour after the injection and was accompanied by a significant increase in plasma glucagon levels, suggesting that the hypergly cemia may be due to a release of glu-
cagon from the alpha cells. No evidence of significant depletion of pancreatic glucagon was observed during the 3 days after treatment nor did glucagon levels decline significantly at any time. It is suggested that, in the rat, CoCla is more “alphacytotropic” than “alphacy totoxic” in its action and is ineffective in inducing even a temporary glucagon deficiency.
T
HE PRECISE EFFECTS of the administration of cobaltous chloride upon the alpha cells have been a matter of interest and dispute for more than a decade. In 1951, Van Campenhout and Cornelisr reported that cobaltous chloride produced morphologic evidence of alpha cell damage when administered to guinea pigs. Similar reports of varying degrees of alpha cell degranulation or damage in dogs,“-” rabbits’-” and rats1?,13 appeared subsequently. The transient hyperglycemic phase which follows cobaltous chloride administration was attributed to an initial excitation of glucagon release,l a view supported by a fall in glucagon content of the pancreas reported to occur during and just after this phase. n,r4-1c,These findings led to early hopes that cobaltous chloride might be used as an agent for the selective destruction of the alpha cells in certain animals. However, conflicting findings have been reported. Subsequent electronmicroscopic studies revealed degenerative changes in the beta cellsr7 and in acinar cells*r~lR of the guinea pig pancreas after cobalt, raising doubts as to the specificity of alpha cell changes. Furthermore, others failed to find any changes in the alpha cellsr”,2” of the glucagon content4*r0*“” of the pancreas in some species after CoClz, while Fodden and Read21 reported a rise in extractable glucagon in rabbits after cobalt treatment. It seemed of interest, therefore, to re-examine these questions by means of a recently developed, highly specific and sensitive immunochemical technic for the assay of gluof cagon. 22 The following is a report of the effects of the administration cobaltous chloride upon the levels of glucagon in the blood and pancreas of the rat. From the Uniuersity of Texas Southwestern Medical School a& Veterans Administration Hospital, Dallas, Texas, and the University of Stdlenbosch, South Africa. Portions of this study will appear the Vnioersity of Stellenbosch.
in a Ph.D.
This study was supported in part by U.S.P.H. Received for publication Feb. 26, 1964.
thesis by J. de V. Lochner,
submitted
at
Grant No. A-2700.
METABOLISLI,VOL. 13, No. 9 ( SEPTEAIBER), 1964
COCL2 EFFECTS
ON GLUCAGON
869
LEVELS
MATERIALS
AND METHODS
Fifty fed male albino rats (Wistar) weighing 250-350 Gm., were given CoCl, intraperitoneally (i.p. 1 as a 1 per cent solution in sterile water at a dosage level of 25 mg./Kg. body weight. Grotqs of 5 rats were sacrificed under nemhutal anesthesia (50 mg./Kg. 1 at 10. 35. 45, 60 minutes, 6 hours, 1 day x~d 3 days, respectively, after the injection. E1cvc.n control rats were given isotonic saline solution 2nd sacrificed in Pairs at 10, 30. 35. 60
minutes, 1 day and 3 days. h’icotinamidc ( 750 mg./Kg.),
I~istopathologic
and
glycemic
which effects
rcdnccs of CoCl,23
the mortality rate was administered
without preventing i.p. as a 15 pu
tkx, cent
solution 5 minute+ prior to the CoCl., or saline injections. However, despite its use, 10 of simiktr 49 rats died in violent convusions within 2 hours after the injcsction, an experience to that of Crc>lltzfeldt and Schmidt.‘Jq Rlootl samplers were obtained in an heparinized syringe by cardi:~c pnncture and the drtc,rmined in duplicate on a Tcchnicon autoannlyzcr by the ferriwmi(lt t 5 Tht> pnncrenscs \verc excised without undue handling of the glandslx tissue, quick-frozen on dry ice, and extracted by the Krnny modification?” of tht: aci(Ialcohol rrlc~thod of Rest et al.3’ l~lood
sugar
mc.thod of H&man.:
RESULTS Rats sacrificed within nn hour of cohaltous chloride administration exhibited striking elevations in the concentrations of blood glucose and plasma glucagon. ,4t 4Fj minutes after injection the mean blood glucose concentration was at :I pk of 2.57 mg. per cent (21.X325), as compared with a mean of 120 mg. per cent (103-134) in all control rats. The pattern of change in mean blood sngar concentration suggests a gradual increase. beginning within 10 minutes of cobalt administration, reaching a maximum level approximately 45 minutes later, and returning to a near control level at 60 minutes (fig. 1). The pattern of change in plasma glucagon concentration paralleled that of the blood glucose concentration to a remarkable degree. In the group of rats sacrificed at 45 minutes after cobalt administration plasma glucagon had risen to a mean of 5.14 mpg. eq./ml., S.D. * 0.71, as compared with an nwrage of 3.18 S.D. * 0.51, in the entire group of control rats and an average of 3.59, S. D. t 0.48, among 7 control rats sacrificed 45 minutes after placebo injection. This statistically significant elevation in glucagon level (p < O.OZ5 ) ww transient, with a return to a near-control value at 60 minutes. The results are summarized in table 1 and figure 1. Because of wide intragroup variation in pancreatic glucagon content, the small number of observations made in this study precludes a meaningful analvsis of qrlantitative changm in pancreatic glucagon content induced bv
870
LOCHNER,
Table I.-Effects Control Time after Injection ____-_
Plasma (mg.
of CoCl,
on Plasma
Rata
All* Times
Glucose
CoClr-Treated Minutes
45 min.
10
30
EISENTRAUT
AND
UNGER
and Glucagon
Rats
Days 60
45
120
157
117
325
148
122
123
130
242
148
62
108
90
117
193
174
263
120
125
RI
119
14x
113
126
132
144
213
Sugar
125
175
192
240
%)
135
156
151
257
141
108
120
108
x7
111
171
93
9G
107
108 125 113 104 114
MeaIl
Plasma
119 2.60
3.50
3.40
4.50
6.10
3.15
3.50
4.80
2.05
3.40
3.60
2.25
4.50
5.60
3.90
3.50
2.55
2.35
3.25
2.80
3.45
3.10
4.60
4.45
2.35
2.85
3.40
3.20
4.20
2.65
3.90
5.00
2.60
3.60
3.00
Glucagon$
3.05
3.20
4.30
3.90
4.40
ecl./ml.)
3.65
4.00
3.30
3.80
3.21
3.98
(mpg.
2.40 2.60
2.90 2.20 2.05 2.90 Meall S.D.
2.96
3.59
(+0.58)
($0.48)
5.14t
2.56
3.30
3.24
3.53
(+0.71)
3.18 t+0.51j *Other
than
tDiffers Placebo fNot
46 minutes.
significantly
injection,
and
quantitatively
from
the
the group comparable
entire sacrificed to
control
group,
10 minutes
mea.wrements
the after
of
control CoCI.:
glucagon
group (p <
in
sacrificed
45
minutes
after
0.05).
pancreatic
extracts
(cf.
Methods).
cobalt administration. The results, summarized in table 2, do, however, reveal that depletion of pancreatic glucagon does not occur in rats under the conditions of this study. DISCUSSION
The ability of CoC12 to cause selective alpha cell damage in the rat is still a matter of conjecture. While some failed to find any reduction in the alphagranularity20~~7~28or a selective concentration of isotopic CoBo in the alpha cells of the rat,13,2g several authorsr2J3 observed varying degrees of alpha-cell degranulation. Eeterhuizen et a1.i2 pointed out that within 10 minutes after the i. p. administration of CoCIZ (25 mg./Kg. body weight), the alpha granules showed a polarization towards the capillaries, followed by a degranulation of some of the alpha cells, while others were not affected at all, an observation made previously by others in other species.5*7*11v1RThe degranulation and vacuolization reached a maximum towards 24 hours, after which the alpha cells again became regranulated to achieve a normal appearance after 3 days, a pattern which can be reconciled with the apparent fluctuations in pancreatic glucagon content observed here. It should be pointed out that various species
COCL-
EFFECTS
ON
GLUCAGON
871
LEVELS
260 ; 220 z ; 180z ; 1402
------_I
c--
k---4 )
loo-
=I
60 -
5.0-
t
I
1
0
TIME
IN
HDURS
12
24
6
Fig. 1.-Effects of CoCl, administration upon the mean plasma glucose (upper panel) and glucagon concentrations. A marked rise in both to a peak at 45 minutes is compatible with an abrupt but transient glucagon release. The “zero-time” specimen is actuallv the mean of values obtained at various intervals after administration of a placebo. ‘The 45minute glucagon value differs significantly (p < 0.05) from both “zero” and the lo-minute values. to cobalt.
differ in their response has also been observed and Read
cobalt
Changes have
increases
in the blood
initial
although The caused
by
enzymes.”
and extreme
toxic effects
of
results
levels of glucose
minutes,
returning
between
the concentration
been
hyperglycemia
cobalt
clearly
and glucagon,
rapidly
toward
with
has been phase
attributed
to
tissues,S,s,ll
sulphydryl
demonstrate
striking
the baseline
within factor
both
a
reported. described,
in the rat. epinephrine
and hepatic
groups correlation
with each rising promptly
of hyperglycemic
pigs
been
this in the Iatter species.
hyperglycemic
variously
administration
In guinea have
glucagon to Fodden
in rabbits.21
CoClo
species.
on the liver and other
interference These
of the pancreas
following
could not confirm
the transient
has
in pancreatic
hyperglycemia’J”
dramatic
and Schmidt2’ confirms
hyperglycemia
lease,““J2J”
plasma
report
glucagon
concentration
and ratsi2J”
Creutzfeldt
The present
reduction
and the dog.:+ according
to vary in different
increase2”
In dogs3,5 rabbitsg-l1
extractable sugar
also been reported
modest
Although
in the guinea pigi4J6
of
reanoxia
respiratory between
the
to peaks at 45
an hour. This parallelism
and hyperglycemia
strongly
872
LOCHNER,
Table B.-Pancreatic _~_
Control
GlUCWXl (m/m.
ea./Gm.
of wet tissue)
Content
C&l:-Treated Minutes __-.-____
Rats
Time after Injection
Glucagon
EISENTRAUT
AND
UNCER
after CoCZ,
Rats Dam
All Times
10
30
45
60
360
3.111
3.6
3.40
2.10
4.10
3.33
1
3
3.42
3.33
2.85
2.1
2.91
4.08
1.57
1.88
2.15
3.23
3.17
2.9
5.45
2.34
1.62
3.96
2.99
3.03
4.08
2.3
2.73
1.32
3.24
4.50
1.62
2.08
3.09
2.5
2.27
2.23
2.56
3.35
2.42
2.16
2.45 3.00 1.88 1.59 3.96 2.39
Mean
2.96
2.63
3.42
2.46
suggests a cause and effect relationship, as suggested by Van Campenhout Cornelis;’ the rapid rise and decline of plasma glucagon concentration
874
LOCHNER,
EISENTRAUT
AND
Ph.D., Predoctoral Research Fellow, Ukversity of Texas, Southwestern Medical School, Dallas, Tex. Present address: Medical student, University of Stellenbosch, Stellenbosch, South Africa.
J. de V. Lochner,
Anne M. Eisentraut,
Chief Research Technician, pital, Dallas, Tex.
V. A. Hos-
Roger H. Unger, M.D., Assistant Professor of Internal Medicine, University of Texas, Southwestern Medical School; Chief, Metabolism Section, V. A. Hospital, Dallas, Tex.
2.93
and are
UNGER
COCL:: EFFECTS
ON GLUCAGON
873
LEVELS
die
V.: Die \,erband tussen die funksionelc aktiwiteit van die alfa-svlle in
13.
pankreas-eilandweefsel en die Ann. I-J”: koolhidraatlnetabolisme. Stcllenbosclr. 36:175-214, 1961. F~dclcn, J. H.: Cytopathologic effects of cobalt on pancreatic islets of many species. Islands of Langerhans and cobaltous chloride. Arch. Path. 61:65-
75, 1956. 14. Bcncosme, S. tion
of
A.,
glllcagon
and to
Frei,
J.:
alpha
Rela-
cells
alpl~n cells of the pancreas. Istanbul, Contrih. Clin. Sci. 2:56-61, 1952. 16. Vrlylstekc, C. A., Cornelis, G., and de I)ovc, C.: Influence dn traitement au cobalt s11r I(& contcnn en factcur HG (111 pancrtaas de cobayr. Arch. Int. Physiol. 60: 128, 1952. 17. Estcrhuizcn, A. C., and Lever, Pancreatic islet cells in the and
C&l,-treated
guinea
pig.
Mari/., S.. and Frei, J.: Further studies on the relationship of glncagon to the alpha ~11 of the pancreas. Canact. J. Biochclll. Physiol. 3.5: 1197-1203, 19s7.
Fodden, J. II., and Read, W. D.: The activity of extracted pancreatic hyperglycemic-glycogenolytic factor aftcsr cohaltous chloride and synthalin A. Encrinol. 54-303-10, 1954. 22. I’nger, R. Il., Eisentraut, A. XI., McCall, XI. S.. and Madison, L. L.: Glucagon antibodies and an immunoassay for glucagon. J. Clin. Invest. 40: 1280-89. 1961. 23. Estcrhllizen. A. C.: Ondersockinge orr
histogenesc
die
en
eilandweefsel
van
26.
Hoffman, method
Path.
tlic
Pharm.
222:487-
W. S.: Rapid photoelectric for the determination of glu-
Kmny, A. J.: Extractable the h~unan pancreas. docrinol. & M&b. 1955.
27. Best, C. H., Haist, J. II.: I>icAt and of pancreas. J. 1939. Ncmhnann,
Xi.,
tronenoptische I’ankrcas normen 29.
fisiol-
pankreas. D. SC. Thesis, Univ. of Stcllenbosch, 1959. Crcutzfeldt, W., and Schmidt, \V.: Ubvr clic Wirknng von Kohaltchloritl a11t den Blutzucker und die Pankrc,asiltseln bei verschiedenen Nageticrcn.
C”X in blood and urine. Chum. 130:51-5.5, 1957.
A fine
19. Bcmcosme, S. A., and Craston, 1). F.: Elastase ac?ivity of the pancreas and its relation to the alpha crlls. Lab. Invest. 7:701-208, 1958.
21.
25.
28.
scopie elcctronique du pancreas cles cobayes traitcs par le cobalt. C. R. Sot. Biol. (Paris) 153:491-92, 1959.
van
Arch. Exp. 512, 1954.
J. I).: normal
structural study. J. Endocrinol. 23: “4.3-52, 1961. 18. Lacy, 1’. E., and Cardeza, A. F.: Micro-
-70. -,
24.
of
the pancreas. Proc. Sot. Exp. Biol. Mctl. 9 1:589-92, 1956. 1.5. Escr, S., and Tuzinsam, P.: Hyperglyccmic-glycogneolytic factor and
morfologic,
ogie
J.
J.
glncagoll Clin.
1.5: 1089-I
Biol. ot Erl10.5,
R. C., and Hitlout, the insulin content I’hysiol. 97: 107-10.
and Wolf, E.: Untersuchungen
unter normalen Stoffwechsellagen.
Elcxktlrs
und abVirchows
Arch. Perth. Anat. 333:54-67, 1960. Ulrich, F., and Copp, I). H.: The WYtabolism of radioactive cobalt ( Co’“)) in normal ant1 Arch. Biochn.
30. Frank, R.:
alloxan cliabetic rats. 31:148-53, 19Sl.
C., Lamarche, M., and Kocarev. Sur lc, mechanisme clc l’hypc~-
glyccmir precocr provoquhe, chez le robaye, par administration dr chlorurc; clr cobalt. C. R. Acad. Sci. 245: 116567, 195:. 31.
Hultquist, chloride
G. T.: Effect of on the blood sugar
the islet cells in rats. 340-42, 1959.
cobaltous level ancl
Expericntia
1.5:
32. Ellis, S., Anderson, H. L., Jr., and Callins, hl. C.: Pharmacologic differcntiation between epinephrinc-and HGF-hyperglycemias: Application in analysis of cobalt-hyperglycc,mi;l. Proc. Sot. Esp. Biol. Med. 84:38388, 19.53. 33.
Lamar&e, RI., and Kocarrv, R.: Action du chlorure clc cobalt sur la pression nrterille du cobnye. C. R. Sot. Biot. (Paris) I Fil:363-65, 1957.
874
LOCHNER,
EISENTRAUT
AND
I. de V. Lochner, Ph.D., Predoctoral Research Fellow, University of Texas, Southwestern Medical School, Dallas, Tex. Present address: Medical student, University of Stellen,bosch, Stellenb’osch, South Africa. Anne M. Eisentraut,
Chief Research Technician, pital, Dallas, Tex.
V. A. Hos-
Roger H. Unger, M.D., Assistant Professor of Internal Medicine, University of Texas, Southwestern Medical School; Chief, Metabolism Sectiou, V. A. Hospital, Dallas, Tex.
UNGER
cagon from the alpha cells. No evidence of significant depletion of pancreatic glucagon was observed during the 3 days after treatment nor did glucagon levels decline significantly at any time. It is suggested that, in the rat, CoCla is more “alphacytotropic” than “alphacy totoxic” in its action and is ineffective in inducing even a temporary glucagon deficiency.
T
HE PRECISE EFFECTS of the administration of cobaltous chloride upon the alpha cells have been a matter of interest and dispute for more than a decade. In 1951, Van Campenhout and Cornelisr reported that cobaltous chloride produced morphologic evidence of alpha cell damage when administered to guinea pigs. Similar reports of varying degrees of alpha cell degranulation or damage in dogs,“-” rabbits’-” and rats1?,13 appeared subsequently. The transient hyperglycemic phase which follows cobaltous chloride administration was attributed to an initial excitation of glucagon release,l a view supported by a fall in glucagon content of the pancreas reported to occur during and just after this phase. n,r4-1c,These findings led to early hopes that cobaltous chloride might be used as an agent for the selective destruction of the alpha cells in certain animals. However, conflicting findings have been reported. Subsequent electronmicroscopic studies revealed degenerative changes in the beta cellsr7 and in acinar cells*r~lR of the guinea pig pancreas after cobalt, raising doubts as to the specificity of alpha cell changes. Furthermore, others failed to find any changes in the alpha cellsr”,2” of the glucagon content4*r0*“” of the pancreas in some species after CoClz, while Fodden and Read21 reported a rise in extractable glucagon in rabbits after cobalt treatment. It seemed of interest, therefore, to re-examine these questions by means of a recently developed, highly specific and sensitive immunochemical technic for the assay of gluof cagon. 22 The following is a report of the effects of the administration cobaltous chloride upon the levels of glucagon in the blood and pancreas of the rat. From the Uniuersity of Texas Southwestern Medical School a& Veterans Administration Hospital, Dallas, Texas, and the University of Stdlenbosch, South Africa. Portions of this study will appear the Vnioersity of Stellenbosch.
in a Ph.D.
This study was supported in part by U.S.P.H. Received for publication Feb. 26, 1964.
thesis by J. de V. Lochner,
submitted
at
Grant No. A-2700.
METABOLISLI,VOL. 13, No. 9 ( SEPTEAIBER), 1964
COCL2 EFFECTS
ON GLUCAGON
869
LEVELS
MATERIALS
AND METHODS
Fifty fed male albino rats (Wistar) weighing 250-350 Gm., were given CoCl, intraperitoneally (i.p. 1 as a 1 per cent solution in sterile water at a dosage level of 25 mg./Kg. body weight. Grotqs of 5 rats were sacrificed under nemhutal anesthesia (50 mg./Kg. 1 at 10. 35. 45, 60 minutes, 6 hours, 1 day x~d 3 days, respectively, after the injection. E1cvc.n control rats were given isotonic saline solution 2nd sacrificed in Pairs at 10, 30. 35. 60
minutes, 1 day and 3 days. h’icotinamidc ( 750 mg./Kg.),
I~istopathologic
and
glycemic
which effects
rcdnccs of CoCl,23
the mortality rate was administered
without preventing i.p. as a 15 pu
tkx, cent
solution 5 minute+ prior to the CoCl., or saline injections. However, despite its use, 10 of simiktr 49 rats died in violent convusions within 2 hours after the injcsction, an experience to that of Crc>lltzfeldt and Schmidt.‘Jq Rlootl samplers were obtained in an heparinized syringe by cardi:~c pnncture and the drtc,rmined in duplicate on a Tcchnicon autoannlyzcr by the ferriwmi(lt t 5 Tht> pnncrenscs \verc excised without undue handling of the glandslx tissue, quick-frozen on dry ice, and extracted by the Krnny modification?” of tht: aci(Ialcohol rrlc~thod of Rest et al.3’ l~lood
sugar
mc.thod of H&man.:
RESULTS Rats sacrificed within nn hour of cohaltous chloride administration exhibited striking elevations in the concentrations of blood glucose and plasma glucagon. ,4t 4Fj minutes after injection the mean blood glucose concentration was at :I pk of 2.57 mg. per cent (21.X325), as compared with a mean of 120 mg. per cent (103-134) in all control rats. The pattern of change in mean blood sngar concentration suggests a gradual increase. beginning within 10 minutes of cobalt administration, reaching a maximum level approximately 45 minutes later, and returning to a near control level at 60 minutes (fig. 1). The pattern of change in plasma glucagon concentration paralleled that of the blood glucose concentration to a remarkable degree. In the group of rats sacrificed at 45 minutes after cobalt administration plasma glucagon had risen to a mean of 5.14 mpg. eq./ml., S.D. * 0.71, as compared with an nwrage of 3.18 S.D. * 0.51, in the entire group of control rats and an average of 3.59, S. D. t 0.48, among 7 control rats sacrificed 45 minutes after placebo injection. This statistically significant elevation in glucagon level (p < O.OZ5 ) ww transient, with a return to a near-control value at 60 minutes. The results are summarized in table 1 and figure 1. Because of wide intragroup variation in pancreatic glucagon content, the small number of observations made in this study precludes a meaningful analvsis of qrlantitative changm in pancreatic glucagon content induced bv
870
LOCHNER,
Table I.-Effects Control Time after Injection ____-_
Plasma (mg.
of CoCl,
on Plasma
Rata
All* Times
Glucose
CoClr-Treated Minutes
45 min.
10
30
EISENTRAUT
AND
UNGER
and Glucagon
Rats
Days 60
45
120
157
117
325
148
122
123
130
242
148
62
108
90
117
193
174
263
120
125
RI
119
14x
113
126
132
144
213
Sugar
125
175
192
240
%)
135
156
151
257
141
108
120
108
x7
111
171
93
9G
107
108 125 113 104 114
MeaIl
Plasma
119 2.60
3.50
3.40
4.50
6.10
3.15
3.50
4.80
2.05
3.40
3.60
2.25
4.50
5.60
3.90
3.50
2.55
2.35
3.25
2.80
3.45
3.10
4.60
4.45
2.35
2.85
3.40
3.20
4.20
2.65
3.90
5.00
2.60
3.60
3.00
Glucagon$
3.05
3.20
4.30
3.90
4.40
ecl./ml.)
3.65
4.00
3.30
3.80
3.21
3.98
(mpg.
2.40 2.60
2.90 2.20 2.05 2.90 Meall S.D.
2.96
3.59
(+0.58)
($0.48)
5.14t
2.56
3.30
3.24
3.53
(+0.71)
3.18 t+0.51j *Other
than
tDiffers Placebo fNot
46 minutes.
significantly
injection,
and
quantitatively
from
the
the group comparable
entire sacrificed to
control
group,
10 minutes
mea.wrements
the after
of
control CoCI.:
glucagon
group (p <
in
sacrificed
45
minutes
after
0.05).
pancreatic
extracts
(cf.
Methods).
cobalt administration. The results, summarized in table 2, do, however, reveal that depletion of pancreatic glucagon does not occur in rats under the conditions of this study. DISCUSSION
The ability of CoC12 to cause selective alpha cell damage in the rat is still a matter of conjecture. While some failed to find any reduction in the alphagranularity20~~7~28or a selective concentration of isotopic CoBo in the alpha cells of the rat,13,2g several authorsr2J3 observed varying degrees of alpha-cell degranulation. Eeterhuizen et a1.i2 pointed out that within 10 minutes after the i. p. administration of CoCIZ (25 mg./Kg. body weight), the alpha granules showed a polarization towards the capillaries, followed by a degranulation of some of the alpha cells, while others were not affected at all, an observation made previously by others in other species.5*7*11v1RThe degranulation and vacuolization reached a maximum towards 24 hours, after which the alpha cells again became regranulated to achieve a normal appearance after 3 days, a pattern which can be reconciled with the apparent fluctuations in pancreatic glucagon content observed here. It should be pointed out that various species
COCL-
EFFECTS
ON
GLUCAGON
871
LEVELS
260 ; 220 z ; 180z ; 1402
------_I
c--
k---4 )
loo-
=I
60 -
5.0-
t
I
1
0
TIME
IN
HDURS
12
24
6
Fig. 1.-Effects of CoCl, administration upon the mean plasma glucose (upper panel) and glucagon concentrations. A marked rise in both to a peak at 45 minutes is compatible with an abrupt but transient glucagon release. The “zero-time” specimen is actuallv the mean of values obtained at various intervals after administration of a placebo. ‘The 45minute glucagon value differs significantly (p < 0.05) from both “zero” and the lo-minute values. to cobalt.
differ in their response has also been observed and Read
cobalt
Changes have
increases
in the blood
initial
although The caused
by
enzymes.”
and extreme
toxic effects
of
results
levels of glucose
minutes,
returning
between
the concentration
been
hyperglycemia
cobalt
clearly
and glucagon,
rapidly
toward
with
has been phase
attributed
to
tissues,S,s,ll
sulphydryl
demonstrate
striking
the baseline
within factor
both
a
reported. described,
in the rat. epinephrine
and hepatic
groups correlation
with each rising promptly
of hyperglycemic
pigs
been
this in the Iatter species.
hyperglycemic
variously
administration
In guinea have
glucagon to Fodden
in rabbits.21
CoClo
species.
on the liver and other
interference These
of the pancreas
following
could not confirm
the transient
has
in pancreatic
hyperglycemia’J”
dramatic
and Schmidt2’ confirms
hyperglycemia
lease,““J2J”
plasma
report
glucagon
concentration
and ratsi2J”
Creutzfeldt
The present
reduction
and the dog.:+ according
to vary in different
increase2”
In dogs3,5 rabbitsg-l1
extractable sugar
also been reported
modest
Although
in the guinea pigi4J6
of
reanoxia
respiratory between
the
to peaks at 45
an hour. This parallelism
and hyperglycemia
strongly
872
LOCHNER,
Table B.-Pancreatic _~_
Control
GlUCWXl (m/m.
ea./Gm.
of wet tissue)
Content
C&l:-Treated Minutes __-.-____
Rats
Time after Injection
Glucagon
EISENTRAUT
AND
UNCER
after CoCZ,
Rats Dam
All Times
10
30
45
60
360
3.111
3.6
3.40
2.10
4.10
3.33
1
3
3.42
3.33
2.85
2.1
2.91
4.08
1.57
1.88
2.15
3.23
3.17
2.9
5.45
2.34
1.62
3.96
2.99
3.03
4.08
2.3
2.73
1.32
3.24
4.50
1.62
2.08
3.09
2.5
2.27
2.23
2.56
3.35
2.42
2.16
2.45 3.00 1.88 1.59 3.96 2.39
Mean
2.96
2.63
3.42
2.46
suggests a cause and effect relationship, as suggested by Van Campenhout Cornelis;’ the rapid rise and decline of plasma glucagon concentration
874
LOCHNER,
EISENTRAUT
AND
Ph.D., Predoctoral Research Fellow, Ukversity of Texas, Southwestern Medical School, Dallas, Tex. Present address: Medical student, University of Stellenbosch, Stellenbosch, South Africa.
J. de V. Lochner,
Anne M. Eisentraut,
Chief Research Technician, pital, Dallas, Tex.
V. A. Hos-
Roger H. Unger, M.D., Assistant Professor of Internal Medicine, University of Texas, Southwestern Medical School; Chief, Metabolism Section, V. A. Hospital, Dallas, Tex.
2.93
and are
UNGER
COCL:: EFFECTS
ON GLUCAGON
873
LEVELS
die
V.: Die \,erband tussen die funksionelc aktiwiteit van die alfa-svlle in
13.
pankreas-eilandweefsel en die Ann. I-J”: koolhidraatlnetabolisme. Stcllenbosclr. 36:175-214, 1961. F~dclcn, J. H.: Cytopathologic effects of cobalt on pancreatic islets of many species. Islands of Langerhans and cobaltous chloride. Arch. Path. 61:65-
75, 1956. 14. Bcncosme, S. tion
of
A.,
glllcagon
and to
Frei,
J.:
alpha
Rela-
cells
alpl~n cells of the pancreas. Istanbul, Contrih. Clin. Sci. 2:56-61, 1952. 16. Vrlylstekc, C. A., Cornelis, G., and de I)ovc, C.: Influence dn traitement au cobalt s11r I(& contcnn en factcur HG (111 pancrtaas de cobayr. Arch. Int. Physiol. 60: 128, 1952. 17. Estcrhuizcn, A. C., and Lever, Pancreatic islet cells in the and
C&l,-treated
guinea
pig.
Mari/., S.. and Frei, J.: Further studies on the relationship of glncagon to the alpha ~11 of the pancreas. Canact. J. Biochclll. Physiol. 3.5: 1197-1203, 19s7.
Fodden, J. II., and Read, W. D.: The activity of extracted pancreatic hyperglycemic-glycogenolytic factor aftcsr cohaltous chloride and synthalin A. Encrinol. 54-303-10, 1954. 22. I’nger, R. Il., Eisentraut, A. XI., McCall, XI. S.. and Madison, L. L.: Glucagon antibodies and an immunoassay for glucagon. J. Clin. Invest. 40: 1280-89. 1961. 23. Estcrhllizen. A. C.: Ondersockinge orr
histogenesc
die
en
eilandweefsel
van
26.
Hoffman, method
Path.
tlic
Pharm.
222:487-
W. S.: Rapid photoelectric for the determination of glu-
Kmny, A. J.: Extractable the h~unan pancreas. docrinol. & M&b. 1955.
27. Best, C. H., Haist, J. II.: I>icAt and of pancreas. J. 1939. Ncmhnann,
Xi.,
tronenoptische I’ankrcas normen 29.
fisiol-
pankreas. D. SC. Thesis, Univ. of Stcllenbosch, 1959. Crcutzfeldt, W., and Schmidt, \V.: Ubvr clic Wirknng von Kohaltchloritl a11t den Blutzucker und die Pankrc,asiltseln bei verschiedenen Nageticrcn.
C”X in blood and urine. Chum. 130:51-5.5, 1957.
A fine
19. Bcmcosme, S. A., and Craston, 1). F.: Elastase ac?ivity of the pancreas and its relation to the alpha crlls. Lab. Invest. 7:701-208, 1958.
21.
25.
28.
scopie elcctronique du pancreas cles cobayes traitcs par le cobalt. C. R. Sot. Biol. (Paris) 153:491-92, 1959.
van
Arch. Exp. 512, 1954.
J. I).: normal
structural study. J. Endocrinol. 23: “4.3-52, 1961. 18. Lacy, 1’. E., and Cardeza, A. F.: Micro-
-70. -,
24.
of
the pancreas. Proc. Sot. Exp. Biol. Mctl. 9 1:589-92, 1956. 1.5. Escr, S., and Tuzinsam, P.: Hyperglyccmic-glycogneolytic factor and
morfologic,
ogie
J.
J.
glncagoll Clin.
1.5: 1089-I
Biol. ot Erl10.5,
R. C., and Hitlout, the insulin content I’hysiol. 97: 107-10.
and Wolf, E.: Untersuchungen
unter normalen Stoffwechsellagen.
Elcxktlrs
und abVirchows
Arch. Perth. Anat. 333:54-67, 1960. Ulrich, F., and Copp, I). H.: The WYtabolism of radioactive cobalt ( Co’“)) in normal ant1 Arch. Biochn.
30. Frank, R.:
alloxan cliabetic rats. 31:148-53, 19Sl.
C., Lamarche, M., and Kocarev. Sur lc, mechanisme clc l’hypc~-
glyccmir precocr provoquhe, chez le robaye, par administration dr chlorurc; clr cobalt. C. R. Acad. Sci. 245: 116567, 195:. 31.
Hultquist, chloride
G. T.: Effect of on the blood sugar
the islet cells in rats. 340-42, 1959.
cobaltous level ancl
Expericntia
1.5:
32. Ellis, S., Anderson, H. L., Jr., and Callins, hl. C.: Pharmacologic differcntiation between epinephrinc-and HGF-hyperglycemias: Application in analysis of cobalt-hyperglycc,mi;l. Proc. Sot. Esp. Biol. Med. 84:38388, 19.53. 33.
Lamar&e, RI., and Kocarrv, R.: Action du chlorure clc cobalt sur la pression nrterille du cobnye. C. R. Sot. Biot. (Paris) I Fil:363-65, 1957.
874
LOCHNER,
EISENTRAUT
AND
I. de V. Lochner, Ph.D., Predoctoral Research Fellow, University of Texas, Southwestern Medical School, Dallas, Tex. Present address: Medical student, University of Stellen,bosch, Stellenb’osch, South Africa. Anne M. Eisentraut,
Chief Research Technician, pital, Dallas, Tex.
V. A. Hos-
Roger H. Unger, M.D., Assistant Professor of Internal Medicine, University of Texas, Southwestern Medical School; Chief, Metabolism Sectiou, V. A. Hospital, Dallas, Tex.
UNGER