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Query: HUMANGGP:034761 (insulin)
 211,843 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We differentiate indirect and direct methods. The indirect methods include the examination of the blood (ESR, blood picture, electrolytes, especially calcium, for the exclusion of hyperparathyroidism, status of fat and liver enzymes, activity of alpha-amylase and lipase. More informative than a serum determination is the measurement of the amylase activity in the 24-hour urine. The detection of chymotrypsin in the stool can be recommended as an investigative test also for use in general practive in collaboration with a central laboratory.- The direct methods include investigation of the duodenal juice with measurement of pH, bicarbonate, of the activities of chymotrypsin, trypsin, lipase and amylase. For excluding of a disturbance of the carbohydrate metabolism in addition to blood sugar determinations, glucose tolerance and tolbutamide tests, the determination of insulin activity is indicated.
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PMID:[Chemical Investigation of Chronic Pancreatitis]. 0 30

Insulin, proinsulin, glucagon and gastrin were determined in extracts of tumors of 27 patients with pancreatic islet cell neoplasia of pancreas, in one patient with nesidioblastosis, in extracts of uninvolved portions of the pancreas in 11 of the tumor patients and of 15 control pancreases. Mean insulin concentration in solitary adenomas and in adenomas of patients with adenomatosis was higher than in control pancreases; however, in all but 1 patient the insulin concentration in neoplastic islet tissue was lower than in islet tissue of control pancreas, assuming islet volume is 1% of pancreas. The percentage of proinsulin was elevated in 52% of tumors. Adenoma insulin content correlated with increments of plasma insulin after tolbutamide administration. Insulin and proinsulin concentrations in pancreas uninvolved by tumor were not suppressed. Fasting plasma glucagon was elevated in patients with islet cell adenomatosis and in patients with islet cell carcinoma some of whom had multiple endocrine adenomatosis. The mean concentration of glucagon in tumors was lower than in control pancreases. Elevated concentration of gastrin was found in some adenomas. The data indicate: 1) insulin-secreting islet cell tumors have decreased storage capacity for insulin, 2) elevated concentration of proinsulin in tumors may be due to decreased capacity to store insulin and in some to decreased conversion of proinsulin to insulin as well, 3) tolbutamide stimulates the exaggerated release of a relatively constant fraction of insulin stored in adenomas. 4) solitary adenomas may contain excess amounts of pancreatic hormones in addition to insulin, 5) elevated plasma glucagon in patients with organic hyperinsulinism may indicate malignancy, microadenomatosis or multiple endocrine adenoma syndrome, and 6) chronic hyperinsulinism and hypoglycemia due to adenoma do not suppress insulin and proinsulin content of uninvolved pancreas.
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PMID:Insulin, proinsulin, glucagon and gastrin in pancreatic tumors and in plasma of patients with organic hyperinsulinism. 1 70

It has been suggested that the carbohydrate-rich diet of chicks after hatching is responsible for the emergence of hepatic enzymes involved in lipogenesis; the injection of glucose to newly hatched chicks gives rise to an appreciable elvation on the activities of acetyl coenzyme A carboxylase and fatty acid synthetase. The present study shows that during the first hours after hatching, there is a natural elevation of glycemia which parallels the increase in acetyl coenzyme A carboxylase activity. However, the administration of hormones which alter the blood glucose levels considerably (insulin, tolbutamide, glucagon and hydrocortisone) did not influence the enzyme activity. The administration of thyroxine, estradiol and cyclic AMP, was also without effect. These results do not support the theory that the increased amount of blood glucose is the natural effector of the induction acetyl coenzyme A carboxylase. They also show that different lipogenic enzymes are not regulated via the same 'operon' since thyroxine or glucagon which alter the level of some enzymes on this pathway did not modify that of the acetyl coenzyme A carboxylase.
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PMID:Development of hepatic acetyl coenzyme A carboxylase in hormone-treated chicks. 1 45

The effect of guanosine on insulin secretion, adenylyl and guanylyl cyclase activities of isolated rat islets of Langerhans was investigated. Guanosine (1-100 micron) inhibited glucose, tolbutamide, theophylline and prostaglandin E2-stimulated insulin secretion although it failed to affect glucagon stimulated secretion. Prostaglandin E2-stimulated adenylyl cyclase activity of islets was inhibited by guanosine although guanosine had no effect on basal, fluoride, glucagon or GTP-stimulated activity. Guanosine markedly decreased basal guanylyl cyclase activity of islets. These results suggest that guanosine may affect insulin release by inhibiting adenylyl and guanylyl cyclase activities in the beta-cell thereby decreasing the intracellular concentrations of cyclic nucleotides. This effect may be important in modulating the secretory response of the islets to a variety of hormonal agents.
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PMID:Effects of guanosine on insulin secretion and adenylyl and guanylyl cyclase activities of isolated rat islets of Langerhans. 1 8

Fifteen patients with non-ketotic hyperosmolar diabetic coma were investigated and compared with ketoacidotic patients. Basal plasma insulin levels were low in all patients (14.8 +/- 1.0 micronU/ml in hyperosmolar coma, 11.0 +/- 1.3 in keto-acidosis), but insulin level increased after intravenous tolbutamide (between 30 and 105 micronU/ml) in eight hyperosmolar comas. Insulin showed no increase in seven hyperosmolar comas and in none of the ketoacidotic patients. In hyperosmolar coma plasma free fatty acids (1710 +/- 197 micronEq/1), triglycerides (3,4 +/- 0,4 g/1) and cortisol levels (49,7 +/- 9,0 microgram/100 ml) were increased, must as in keto-acidosis. Growth hormone (1,7 +/- 0,1 ng/ml) was normal, unlike the case in keto-acidosis. Plasma lactate concentrations were elevated and account for the frequent mild acidosis found in hyperosmolar coma. In spite of the low peripheral "insulin/glycemia ratio", the positive response to tolbutamide in half of the hyperosmolar cases suggests a less complete pancreatic deficiency than in keto-acidosis. The plasma high free fatty acid and triglyceride levels suggest that the lack of ketosis is not due to inhibition of lipolysis but could be a consequence of inhibition of hepatic ketogenesis.
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PMID:[Hormone and metabolic profile in diabetic hyperosomolar coma. Plasma insulin response to intravenous tolbutamide (author's transl)]. 3 82

The aim of the present study was to evaluate possible hemodynamic effects of somatostatin in insulin-dependent diabetic subjects. For this purpose, 7 insulin-requiring juvenile-onset diabetics were submitted to a short-term infusion of cyclic somatostatin (250 micrograms/h, over 2 h) or saline in randomized order. Somatostatin infusion resulted in a progressive and significant decrease in heart rate, stroke volume, cardiac index and velocity circumferential fiber; on the other hand, left ventricular ejection time was augmented by somatostatin. None of these effects was seen in the saline control study. We conclude that somatostatin exerts a negative inotropic effect in insulin-dependent diabetes.
Acta Diabetol Lat
PMID:Hemodynamic effects of somatostatin in insulin-dependent diabetic subjects. 4 64

This study was aimed at evaluating the effect of theophylline, a drug that increases the intracellular concentrations of cAMP by inhibiting phosphodiesterase activity, on somatostatin (SRIF)-mediated inhibition of insulin secretion in man. Acute insulin response (AIR) to i.v. glucose (mean change 3-10 min) was almost totally suppressed by SRIF (500 micrograms/h) and glucose utilization was reduced (p less than 0.0001). These SRIF-induced decreases failed to be eliminated by a concurrent infusion of theophylline (100 mg as a loading dose followed by a constant infusion of 5 mg/min). Theophylline alone resulted in a significant increase in both AIR (p less than 0.01) and glucose removal rates (p less than 0.05). Thus, our data disprove the involvement of the phosphodiesterase enzymes in the inhibitory action of SRIF on glucose-induced insulin secretion in man.
Acta Diabetol Lat
PMID:Somatostatin and insulin secretion in man. II. The effect of theophylline. 4 65

Diazoxide 5 mg/kg/day was administered to four normal subjects for five days and, together with insulin, to ten diabetic subjects for seven days. In every case there was a substantial increase in the insulin response to combined stimulation of the pancreatic beta cells with 1 mg of glucagon and 2 g of tolbutamide given intravenously. Similar increases were not seen in four diabetics who received placebo with insulin. It is likely that the observed improvements reflected increased insulin stores which resulted from diazoxide inhibition of insulin release. These findings suggest that poor insulin responses in diabetics may be due, at least in part, to chronic overstimulation of the beta cells. Pharmacological agents such as diazoxide, which inhibit glucose-induced insulin release, may have a place in preserving and restoring insulin secretion in diabetes.
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PMID:Improvement in insulin secretion in diabetes after diazoxide. 5 17

The historical development of research on islets transplantation is briefly reviewed followed by a description of a technique using Ficoll gradient separation to obtain islets of Langerhans from the rat pancreas. It was possible to increase the number of islets obtained with this procedure by modifying it in several ways. The islets were then transplanted in an isologue manner into rats with streptocotocin-induced diabetes. The effect of transplantation on glucose metabolism in these rats was evaluated both by determination of the general symptoms typical for diabetes as well as by the performance of such functional tests as IVGTT, GAC and tolbutamide test. The islets could be transplanted into various locations, but it was found that positive results were obtained only if the liver was the site of application and if than 2100 islets were used. Three hours after transplantation normalization of blood sugar levels and serum insulin could be observed; these levels remained stable over 18 months. It was possible to transplant in the same animal several times. This had an effect on the metabolism which was equivalent to the sum of the separate transplants. By means of both light and electron microscope examination the morphological changes which the transplanted islets underwent at the site of transplantation were observed.
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PMID:[Transplantation of isolated islands of Langerhans for the treatment of diabetes mellitus]. 9

McN-3495, a new compound unrelated strucuturally to the sulfonylureas or phenformin, has been found to produce a hypoglycemic effect in nondiabetic rats, dogs, mice, and monkeys. The minimum effective dose of McN-3495 that lowers fasting blood glucose and improves glucose tolerance was found to be about 2.5 to 5 mg-per kilogram, per os, except in fasted monkeys, in which a tenfold greater potency was observed. When McN-3495 was given repeatedly for three to five days, no tolerance to the hypoglycemic activity occurred and no changes in other biochemical parameters were observed. In addition to being three to four times more potent than tolbutamide, McN-3495 also differs from the sulfonylureas in lowering blood glucose concentrations of streptozotocin-diabetic rats and db/db mice, and, moreover, oral administration to normal fasted dogs did not produce the characteristic rise in insulin concentrations observed with tolbutamide. Furthermore, unlike the biguanides, McN-3495 can lower dog and rat fasting blood glucose concentrations and can improve glucose tolerance whether the glucose is administered orally or parenterally. However, McN-3495, as phenformin, fails to work in totally depancreatized dogs.
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PMID:A pharmacologic profile of McN-3495 [N-(1-methyl-2-pyrrolidinylidene)-N'-phenyl-1-pyrrolidinecarboximidamide], a new, orally effective hypoglycemic agent. 9 77


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