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Query: UMLS:C0011849 (diabetes)
 277,896 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

One hour following intravenous streptozotocin, rat pancreases were perfused in situ, and , in contrast to saline-injected controls a marked decrease of insulin secretion was observed. In these streptozotocin-treated animals, baseline glucagon secretion was enhanced when the perfusate glucose concentration was either 80 mg./100 ml. or 300 mg./100 ml. In addition there was hypersecretion of glucagon in response to arginine. Exogenous insulin (20,000 muU./ml.) could suppress glucagon secretion when endogenous secretion was plentiful. Baseline and arginine-stimulated glucagon secretion of the streptozotocin treated animals was not suppressed by large amounts of glucose and insulin to the degree seen in control animals. The glucagon rise in response to an abrupt fall of glucose from 80 mg./100 ml. to 25 mg./100 ml. was not significantly higher in the control group than in the streptozotocin group. The results seen with epinephrine were in sharp contrast to those found with arginine. Epinephrine-stimulated glucagon secretion was not enhanced in the streptozotocin group. In addition, epinephrine-induced secretion could be suppressed by exogenous insulin in both the control and streptozotocin groups. The differences may be secondary to differences of endogenous insulin secretion. The present results are compatible with the hypothesis that local insulin secretion can exert a significant suppressive effect upon the alpha cell and that the inhibition of glucagon secretion by glucose is partially mediated by this mechanism. Furthermore, anomalous local insulin secretion may contribute to the abnormal glucagon secretion of diabetes mellitus.
Diabetes 1976 Apr
PMID:Glucagon secretion from the perfused pancreas of streptozotocin-treated rats. 13 25

Male Wistar rats were treated with an i.v. dose of 100 mg/kg of Streptozotocin (STZ). Either 5 days or 1, 2 or 3 months after induction of diabetes, the adrenal function of these animals was studied. Short course diabetes (5 days) was accompanied by adrenal hypertrophy and high plasma corticosterone levels; during later periods the diabetic rats consistenly showed signs of adrenal hyperactivity, yet both adrenal weight and plasma corticosterone tended to be lower than in the 5 day-treated animals. Adrenal incubations with 14C-progesterone showed that 5 days and one month diabetic animals synthesized more deoxycorticosterone than controls; production of corticosterone and 18-hydroxydeoxycorticosterone was normal at all time periods studied. Synthesis of 18-hydroxycorticosterone, a compound which affects sodium metabolism, was increased in 5 day-treated rats; thereafter, the function of the zona glomerulosa seemed to be impaired in diabetic rats. These results suggest that early after induction of diabetes there is adrenal hyperfunction of the mixed type (i.e. gluco and mineralcorticoid), and that in the later periods (2-3 months), the deranged metabolism of the diabetic rat acts as a chronic stress.
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PMID:The influence of streptozotocin diabetes on adrenal function in male rats. 13 18

Insulin has been shown to lower cyclic AMP (cAMP) levels in hormonally sensitive tissue. The mechanism by which this lowering occurs has not yet been fully defined. We studied the effects of insulin on rat adipose tissue cyclic nucleotide phosphodiestrase (PDE) in an incubation system. The adipose tissue used was from both normal animals and animals rendered diabetic by intravenous injections of streptozotocin. Rat epididymal fat pads were incubated in a Krebs-Ringer bicarbonate-4% albumin system with O, 100, 1,000 or 10,000 PU/ml insulin (INS); epinephrine (EPI) or glucagon (GLU) at several different concentrations. After 15 min of incubation, each tissue was homogenized, centrifugated, and the supernatant assayed for cAMP PDE activity using the breakdown of (3-H)cAMP. The data was used to characterize cAMP PDE into apparent high and low K-m PDE components. In the normal animals, INS increased Vmax of the low Km PDE components; 100 pU/ml INS, 30%, 1000 p1/ML INS, 40; and 10,000 pU/ml INS, 20%. In contrast, streptoxotocin diabetes lowered this Vmax by 30%. In the diabetic animals, INS also increased Vmax by 30%. In the diabetic animals, INS also increased Vmax of the low Km PDE component; 100 pU/ml INS, 30%; 1000 pU/ml INS, 50% and 10,000 pU/ml INS, 100%. Epinephrine at 1, 10, and 100 pg/ml stimulated low Km cAMP PDE activity by 67%, 73% and 44% respectively. The stimulatory effect of EPI on both the low and high Km cAMP PDE activity was neutralized by propranolol or adenosine. In comparison to EPI, GLU at very low concentrations, 10-9M, stimulated low Km cAMP PDE. These studies suggest that some of the biologic actions of insulin, an antilipolytic substance, are mediated through activation of low Km PDE. Furthermore, this enzymatic activity is lower in experimental diabetes. The stimulation of low Km PDE by lipolytic hormones may reflect a long-range protective action of these agents.
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PMID:Effect of insulin and lipolytic hormones on cyclic AMP phosphodieterase activity in normal and diabetic rat adipose tissue. 16 58

1. Epinephrine-induced increase in rat liver cyclic AMP in vivo was potentiated when the circulating insulin was suppressed by injection of anti-insulin serum or by induction of diabetes. Consequently, phosphorylase was activated, glycogen synthetase was inactivated and glycogen accumulation induced by glucose load was prevented by epinephrine in the insulin-deficient rats to a much larger extent than in normal rats. 2. Insulin lack was effective in potentiating epinephrine-induced increase in liver and muscule cyclic AMP even after the treatment of rats with theophylline; the potentiation could not be solely accounted for by the inhibition of cyclic AMP phosphodiesterase. Thus, it is likely that insulin lack enhaces epinephrine activation of adenylate cyclase. 3. Unlike epinephrine, glucagon increased liver cyclic AMP to essentially the same extent whether the rat was treated with anti-insulin serum or not. 4. Based on the difference in dose-response curves between normal and insulin-deficient rats, a possibility is discussed that there are two adenylate cylase in the liver with higher and lower affinities for epinephrine and that circulating insulin blocks the high affinity enzyme selectively.
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PMID:Attenuation of epinephrine-induced increase in liver cyclic AMP by endogeneous insulin in vivo. 18 27

The effects of insulin and adrenaline on cyclic AMP (cAMP) levels in diaphragms of normal, streptozotocin-diabetic and insulin-treated diabetic rats were studied. Adrenaline caused a biphasic rise in cAMP with peak values of cAMP within the first few minutes. Diaphragms of diabetic rats showed an increased responsiveness to adrenaline. Injection of insulin to diabetic rats normalized the rise in cAMP after addition of adrenaline. There was no difference in basal levels of cAMP between diaphragms of normal, diabetic or insulin-treated diabetic rats. Insulin in vitro did not affect basal cAMP-levels or the release of cAMP from the tissue but significantly decreased adrenaline-induced peak levels of cAMP. This effect of insulin was abolished by theophylline. The results of the present study suggest that experimental diabetes is associated with changes of the adenylate cyclase and/or phosphodiesterase enzyme activities in skeletal muscle resulting in an increased responsiveness to adrenaline. Since insulin in vitro depressed the adrenaline-induced elevation of cAMP the increased responsiveness in diaphragms of diabetic rats might be attributed to the specific lack of insulin.
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PMID:Effect of insulin and adrenaline on cyclic AMP in the diaphragm of normal and diabetic rats. 19 69

Some hypothesized risk factors in chronic open-angle glaucoma were investigated in a sample of 87 patinets with glaucoma and 87 matched controls. A significant positive association was found with diabetes, a systolic blood pressure/intraocular pressure (BP/IOP) ratio less than 5.75, and the taking of medication for systemic hypertension. No significant association was found with a history of smoking or an elevated systemic blood pressure. Analysis indicates that the systolic BP/IOP index may be useful as a screening test for the detection of glaucoma in samples where the prevalence of glaucoma is high.
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PMID:Relative risk factors in chronic open-angle glaucoma: an epidemiological study. 32 56

The role of calcium flux in mediating epinephrine modification of insulin release was investigated by using lanthanum, an inhibitor of calcium flux, in the in vitro perifusion system. Lanthanum inhibits insulin secretion stimulated by glucose and by acetylcholine to basal levels. Epinephrine and lanthanum have additive effects in inhibiting insulin secretion to glucose stimulation. The effect of epinephrine prestimulation on insulin secretion to subsequent glucose challenge varies markedly, depending on the presence or absence of bicarbonate ion: epinephrine priming is reversed in the absence of bicarbonate, and effect possibly related to reduced calcium uptake. In the presence of bicarbonate, lanthanum blocks the priming effect of epinephrine on insulin secretion. The data further support the postulated role of calcium in adrenergic effects on beta cell function.
Diabetes 1979 Jan
PMID:Effects of calcium, lanthanum, and bicarbonate ion on epinephrine modification of insulin release in vitro. 36 54

1. Regulation of gluconeogenic substrate supply and modulation of the gluconeogenic pathway in the liver are both important in the control of gluconeogenesis by glucocorticoids. 2. Adrenal deficiency decreases the release of gluconeogenic and other amino acids from skeletal muscle during starvation. The effect is reversed by glucocorticoid replacement. The changes in amino acid release are accompanied by similar alterations in tissue amino acid levels and are not explained by alterations in net protein breakdown. Glucocorticoids do not alter protein catabolism and cause a small inhibition of protein synthesis. The biochemical alterations underlying the changes in amino acid metabolism induced by these steroids remain to be elucidated. Glucocorticoids may also regulate the supply of gluconeogenic substrates through permissive effects on the lipolytic action of catecholamines and other hormones in adipose tissue and on the glycogenolytic action of catecholamines on skeletal muscle. 3. Glucocorticoids are required for the increases in gluconeogenesis in starvation and diabetes. Part of their action is exerted directly on the liver and appears to involve modulation of P-enlopyruvate carboxykinase levels. Glucocorticoids increase the synthesis of this enzyme apparently through effects at the level of transcription. 4. Glucocorticoids exert permissive effects on the stimulation of gluconeogenesis in the liver by glucagon and epinephrine. The steroids are not required for cAMP generation or protein kinase activation by these hormones, but appear to act by maintaining the responsiveness of certain enzymes to the effects of the cAMP and alpha-adrenergic systems. It is proposed that this involves the maintenance of a normal intracellular ionic environment.
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PMID:Regulation of gluconeogenesis by glucocorticoids. 38 91

Total, free, and conjugated urinary catecholamines and their metabolites are studied in diabetes before and after treatment. There are abnormalities in catecholamines metabolism and their metabolites caused by the diabetic condition. The 24 hour urinary excretion of the total catecholamines is significantly increased in diabetics. Epinephrine, as a free fraction, conjugated fraction, and, consequently, as a total metabolite, is significantly increased. No change in dopamine concentration is observed in diabetes although dopamine is known to inhibit insuline release. No sex difference is, however, observed in the diabetic patients with regards to the catecholamines excretion. After controlling the diabetic state, abnormalities in catecholamine metabolism and their metabolites are normalized.
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PMID:Urinary catecholamines and their metabolites in diabetes. 78 21

Norepinephrine, epinephrine, and dopamine concentrations were studied in the cardiovscular system of postmortem material obtained from six long-term diabetics and six control subjects. Norepinephrine concentration was considerably reduced in the cardiovascular system of the diabetic patients. The mean norepinephrine concentration in the apex of the heart, the radial artery, the posterior tibial artery, and the femoral artery in the diabetics averaged 6, 9, 12, and 20 per cent, respectively, of the corresponding mean values in the controls. Epinephrine was present in the cardiovascular system in the controls but in small amounts in comparision with norepinephrine. There was no correlation between the epinephrine and the norepinephrine concentrations in the tissue. In the diabetics the epinephrine concentration in the heart and in the arteries did not differ from the values obtained in the controls. The dopamine concentration averaged 11 per cent of the norepinephrine concentration in the cardiovascular system in the controls. There was a strong correlation between tissue concentrations of dopamine and of norepinephrine. In the diabetics the dopamine concentration was reduced, but relatively less than that of norepinephrine, and constituted 53 per cent of the norepinephrine concentration. It is suggested that the depletion of the norepinephrine stores in the heart in diabetic patients may in part be responsible for their reduced survival rate in acute myocardial infarction.
Diabetes 1976 Jan
PMID:Norepinephrine, epinephrine, and dopamine contents of the cardiovascular system in long-term diabetics. 124 67


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