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Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The mechanisms controlling secretion of glucagon and other pancreatic hormones were studied in a patient affected with multihormone-secreting islet-cell tumor. Fasting glucagon levels (3,000 pg./ml.) rose to 10 ng./ml. following arginine stimulation. While oral glucose load and intravenous glucose infusion did not suppress glucagon secretion, insulin administration induced a prompt depression in glucagon levels. Glucagon, insulin, and gastrin levels were suppressed by somatostatin while calcium infusion caused a paradoxical increase. It is suggested that only some of the stimulation-inhibition mechanisms were conserved in this case of glucagon-secreting pancreatic tumor.
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PMID:Suppression and stimulation mechanisms controlling glucagon secretion in a case of islet-cell tumor producing glucagon, insulin, and gastrin. 0 26

The retention of degradation of insulin by isolated perfused liver have been examined. Noncyclically perfused livers from streptozotocin-diabetic rats retained 25% and degraded 10% of 125I-insulin administered as a 1-min pulse. On gel filtration (Sephadex G50F), the degradation products released into the vascular effluent eluted in the salt peak. During the 45-min interval after the end of the 125I-insulin infusion, 0.19% of the total dose was excreted in the bile. 60-90% of this material consisted of iodinated, low-molecular-weight degradation products. Inclusion of native insulin with the 125I-insulin in the pulse depressed both the retention and degradation of iodinated material; however, this reflected increased retention and degradation of the total insulin dose (125I-insulin plus native hormone). The log of the total amounts of insulin retained and degraded were linearly related to the log of the total amount of insulin infused at concentrations between 12.7 nM and 2.84 muM. Increasing the amount of native insulin in the infused pulse also depressed the total amount of iodinated material found in the bile and led to the appearance in the bile of intermediate-sized degradation products that did not simultaneously appear in the vascular effluent. Addition of high concentrations of glucagon to the infused 125I-insulin had no effect on the retention or degradation of the labeled hormone, or on the apparent size and amount of iodinated degradation products found in the vascular effluent or in the bile. Preinfusion of concanavalin A inhibited both 125I-insulin retention and degradation. A greater depression by concanavalin A of degradation than binding was also observed with isolated hepatocytes. In contrast to 125I-insulin, the retention and degradation of two iodinated insulin analogues of relative low biological potency, proinsulin and desalanyl-desasparaginyl insulin, were small. The amount of radioactivity appearing in the bile after infusion of these analogues was almost negligible. However, degradation products of these analogues that appeared in the bile and in the vascular effluent was qualitatively similar to those found after the infusion of 125I-insulin. Our findings suggest that the rapid initial uptake of 125I-insulin after its infusion into noncyclically perfused liver, as well as its subsequent degradation, behaves in a qualitatively similar fashion to the binding of 125I-insulin and its degradation by isolated rat hepatocytes. This uptake and the subsequent phase of degradation may be attributable to binding of insulin at specific recognition sites, preliminary to its transfer to a degradative site(s) presumed to be located inside the cell.
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PMID:Retention and degradation of 125I-insulin by perfused livers from diabetic rats. 13 20

Crude mediators from stimulated rabbit peritoneal leukocytes (LEM) engender numerous physiologic alterations in rats, which are similar to those observed during infection. One hour after the intraperitoneal injection of crude LEM, plasma insulin and glucagon concentrations are elevated; at 2 h the hormonal alterations are manifested by a 30% increase in hepatic cyclic adenosine 3',5'-monophosphate (cAMP), glycogen depression, and uptake of 14C-labeled nonmetabolizable amino acid analogues (AA). Plasma hormone concentrations reach maximum levels by 5 h and decline by 24 h. The hepatic concentrations of AA parallel the insulin and glucagon responses and correlate with the inverse of insulin/glucagon molar ratio. In spite of mobilization of hepatic glycogen evident at 5 h, plasma glucose concentrations were transiently depressed. Plasma insulin, glucagon, and hepatic AA concentrations were dose dependent. Plasma insulin and glucagon responses to crude LEM may explain increases in hepatic cAMP, uptake of AA, and glycogenolysis as well as hypoglycemia. These data partially characterize the role of crude LEM, provide an explanation for the stimuli-inducing hyperglucagonemia and hyperinsulinemia during infection. They implicate the endocrine pancreas as a factor regulating the host's metabolic response to infection.
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PMID:Effect of leukocytic endogenous mediators on endocrine pancreas secretory responses. 19 70

1 Quantitative studies were made on the glucose release from rabbit liver slices in vitro induced by a range of concentrations of (-)-adrenaline (Ad), (-)-isoprenaline (Iso), glucagon and adenosine 3',5'-monophosphate (cyclic AMP) in the presence and absence of several concentrations of dihydroergotamine (DHE). 2 DHE (3.16 X 10(-6) M) shifted the Ad log concentration-response (LCR) curve to the right and also reduced the maximum response; at a higher concentration (3.16 x 10(-5) M) it produced a greater shift to the right of the LCR curve and caused a reduction in the slope and a larger depression of the maximal responses. The LCR curve to Iso was similarly affected by this higher concentration of DHE. 3 DHE (1 X 10(-5) M) produced no significant effect on the LCR curves of glucagon or cyclic AMP and even at 1 x 10(-4) M DHE caused only a slight depression of the maximal responses to both agonists without any modification of the lower major portions of the curves. 4 These data indicate a selective antagonism by DHE at the rabbit liver adrenoceptor and, since the maximal responses to catecholamines were depressed by a lower concentration of DHE than was required to produce a slight depression of the responses to glucagon and cyclic AMP, the antagonism of DHE against catecholamines does not appear to be at a site beyond the formation of cyclic AMP, but rather at a site more intimately related to the adrenoceptor.
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PMID:Differences in dihydroergotamine antagonism of glucose release by catecholamines, glucagon and adenosine 3',5'-monophosphate in rabbit liver slices. 21 Aug 74

Studies in vitro and with intact chicks support the view that liver is the major site of lipid biosynthesis in the chicken. Adipose tissue is relatively unimportant as a site of fatty acid biosynthesis in this species although it does have the ability to esterify fatty acids to triglycerides. The available evidence, therefore, suggests that in the chicken, and presumably other avian species, fatty acids are synthesized in liver and are transported as triglycerides in the plasma low-density lipoproteins to the adipose tissue for storage. Fasting, even for short periods of time, markedly depresses the capacity for hepatic lipogenesis in the chick. Food restriction for 2 hr. depresses hepatic lipogenesis by about 90% and refeeding for 1 hr./or/the intravenous administration of glucose or fructose restores the lipogenic capacity. Feeding diets high in fat or protein cannot be adequately explained on the basis of the reduction of dietary carbohydrate which accompanies increased dietary protein or fat levels. Dietary fat and protein appear to exert their effects on hepatic lipid synthesis by different mechanisms. The depression in hepatic fatty acid synthesis brought about by fasting or fat-feeding is accompanied, and probably preceded, by an increased plasma free fatty acid level. Under these conditions hepatic fatty-acyl CoA levels increase while free CoA levels are reduced. Long-chain acyl CoA derivatives are capable of inhibiting acetyl CoA carboxylase activity as well as citrate transport. The reduced availability of free CoA may limit the citrate cleavage reaction. Dietary alterations influence the hepatic lactate-pyruvate ratio of chicks, however the changes observed are not always consistent with the changes observed in rat liver. Chicks fed high-protein diets have a decreased hepatic lactate/pyruvate ratio indicative of a more oxidized cytoplasmic environment. This change in redox state may be associated with control of fatty acid synthesis in chicks fed high-protein diets. Thyroxine and glucagon affect hepatic fatty acid synthesis in the chick, however insulin appears to play a lesser role.
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PMID:Lipid biosynthesis in the chick. A consideration of site of synthesis, influence of diet and possible regulatory mechanisms. 24 Jan 59

1. Six weeks after the injection of streptozotocin at 125 mg/kg i.p. in the AV line nondiabetic Chinese hamsters, the animals showed hyperglycemia, increased kidney, pancreas and stomach weights and stomach glucagon contents and depletion of insulin and glucagon in the pancreas. 2. Plasma beta-D-galactosidase and N-acetyl-beta-D-glucosaminidase were elevated; whereas alpha-D-glucosidase was decreased and alpha-D-galactosidase remained unchanged in the plasma. 3. In the kidney, streptozotocin-diabetes led to depression of alpha-D-mannosidase, beta-D-fucosidase and N-acetyl-beta-D-glucosaminidase activities in both 12,000 g supernatant and precipitate fractions, decreases in alpha-D-glucosidase in the supernatant only and no change in alpha-L-fucosidase, alpha-D-galactosidase, beta-D-galactosidase and beta-D-glucuronidase. 4. In the liver, significant increases in N-acetyl-beta-D-glucosaminidase, alpha-D-galactosidase, beta-D-galactosidase, beta-D-fucosidase, beta-D-glucosidase and alpha-D-mannosidase were found in either the supernatant or the precipitate fraction of the diabetic animals. The data indicate diabetes-dependent tissue-specific changes in glycohydrolases in the Chinese hamster.
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PMID:Alterations in glycohydrolase activities in streptozotocin-diabetic Chinese hamsters (Cricetulus griseus). 31 16

The effect of fasting, glucose, and glucagon injection on pyruvate metabolism of rat liver mitochondria was studied. Fasting for 24 h caused a) a twofold increase in mitochondrial pyruvate uptake, b) fivefold increase in CO2 fixation, and c) no change in pyruvate decarboxylation. Injection of glucose to fasted rats 2 h prior to preparation suppressed by one-half the increase in mitochondrial pyruvate uptake and CO2 fixation and increased hepatic pyruvate content. Injection of glucagon together with glucose abolished the depression of pyruvate uptake by glucose but did not prevent the decrease in mitochondrial CO2 fixation or hepatic ketone content caused by glucose alone. The effects of insulin injection resembled that of glucose in decreasing hepatic ketone content, but differed by increasing pyruvate uptake without much change in CO2 fixation. It is concluded that the increase in gluconeogenesis induced by fasting is due to an increase in pyruvate uptake and carboxylation by hepatic mitochondria. The latter is due to the increased mobilization and oxidation of fatty acids induced by reciprocal changes in insulin and glucagon.
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PMID:Nutritional and hormonal regulation of pyruvate metabolism in the liver. 44 69

Bombesin acts within the brain to produce a prompt and sustained hyperglycemia, hyperglucagonemia, and relative or absolute hypoinsulinemia. Bombesin does not decrease plasma glucose turnover. Acute adrenalectomy but not hypophysectomy prevents hyperglycemia and hyperglucagonemia after intracisternal administration of bombesin. Administration of bombesin into the lateral ventricle of awake, unrestrained animals results in elevation of plasma glucose, preceded by a significant increase in plasma epinephrine and no increase in plasma norepinephrine or dopamine. Systemic administration of somatostatin prevents bombesin-induced hyperglycemia and hyperglucagonemia. These data support the conclusion that bombesin acts within the brain to increase sympathetic outflow resulting in increased adrenalmedullary epinephrine secretion, followed by depression of plasma insulin and elevation of plasma glucagon and glucose.
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PMID:Central nervous system action of bombesin: mechanism to induce hyperglycemia. 46 25

The effect of intravenous somatostatin on blood levels of metabolites and hormones has been examined in normal subjects who performed a 30-minute period of bicycle exercises at 70% maximal exercise capacity. The results have been compared with control studies in the same subjects. Measurements were made of blood levels of lactate, glucose, free fatty acids, glycerol, acetoacetate, 3-hydroxybutyrate, insulin, glucagon, growth hormone (hGH) and prolactin. Growth hormone and glucagon release were suppressed during exercise with somatostatin and there was a subsequent elevation during recovery. There was slight post-exercise depression of insulin, but no alteration of plasma prolactin secretion. Blood glucose was reduced during exercise with somatostatin and increased during recovery. The elevation of ketone bodies after exercise was greater in the investigation with somatostatin, but there were no significant changes in other metabolites. Somatostatin, although causing inhibition of hGH release, appeared to have no significant effect upon fatty acid mobilization during exercise.
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PMID:The effect of somatostatin on metabolic and hormonal changes during and after exercise. 47 77

The effect of somatostatin (SRIF) on glucagon and insulin secretion was examined in fed and fasted sheep. This was related to changes in glucose production. Infusion of SRIF at 80 micrograms/h caused a marked reduction in plasma glucagon concentrations. However, the insulin response to SRIF infusion was not consistent; its concentrations decreased occasionally, but often did not change. The depression of glucagon was not associated with a significant reduction in blood glucose concentrations in either fed or fasted sheep, but was associated with a reduction in glucose production by 12--15%. The inhibitory effect of insulin on glucose production was not markedly increased by glucagon deficiency. Infusion of insulin at 1.17 U/h with SRIF decreased glucose production only an additional 10%. Thus, it appears that under basal conditions pancreatic hormonal influences on hepatic glucose production were relatively small in sheep. This implies that under normal conditions in sheep, substrate supply has a much greater impact on hepatic glucogenesis than do hormones.
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PMID:Effect of somatostatin suppression of glucagon secretion on glucose production in sheep. 49 97


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