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Biomedical subjects

T Taminato

Publications and source records attributed to T Taminato.

At least 55 records · Page 3Linked to original sources
PubMed1985

Comparison of somatostatin-28 and somatostatin-14 clearance by the perfused rat liver.

The hepatic clearances of somatostatin (SS)-28 and SS-14 by the perfused rat liver were compared, using a recirculating, plasma-free, erythrocyte-containing perfusion system. The disappearance rate constant, half time, clearance, and hepatic extraction ratio when 1.2 nM SS-28 was added to the perfusate were 0.0221 +/- 0.0051 min-1, 36.6 +/- 7.6 min, 0.34 +/- 0.08 mL/min, and 17.2 +/- 3.9%, respectively. The corresponding values obtained when SS-14 was added to the perfusate were 0.0405 +/- 0.0022 min-1, 17.3 +/- 1.0 min, 0.71 +/- 0.05 mL/min, and 35.4 +/- 2.6%, respectively. The differences between the SS-28 and SS-14 indices were all statistically significant. In addition, the perfusates with SS-28 added were eluted on Sephadex G-25 fine columns and somatostatinlike immunoreactivity (SLI) was determined. No SS-14 was found in perfusate containing SS-28 at both 5 and 30 min after the beginning of the perfusion. To investigate whether or not the liver plays an important role in the clearance of SS-28 or the conversion of SS-14 in vivo, the plasma disappearance of 2 micrograms SS-28 was compared in the whole rat and the functionally hepatectomized model. The half time of plasma SS-28 was 1.43 +/- 0.12 min in the whole rat, significantly shorter than the 2.20 +/- 0.14 min in the hepatectomized model. Gel filtration of plasma extract samples at 0.5 min after the SS-28 injection showed two major peaks of SLI: a first peak corresponding to SS-28 and a second peak coeluted in the position of SS-14 in both the whole rat and the hepatectomized model. At 4 min after the SS-28 injection, the first peak disappeared and only a small second peak was observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Effects of insulin on altered mineral and vitamin D metabolism in streptozotocin-induced diabetes.

In order to ascertain whether or not abnormal mineral and vitamin D metabolism in diabetes can be reversed by insulin therapy, plasma calcium, ionized calcium, phosphorus, parathyroid hormone (PTH) and vitamin D metabolites were measured in control, streptozotocin (STZ) diabetic and insulin-treated diabetic rats. Blood glucose levels in diabetic rats treated with insulin decreased to normal. The low plasma calcium and ionized calcium levels in diabetic rats were found to be normal in insulin-treated diabetic rats. An elevated PTH level was observed in the diabetic group, but it was at normal levels in the insulin-treated diabetic group. Plasma 25-hydroxyvitamin D (25(OH)D) and 24,25-dihydroxyvitamin D (24,25(OH)2D) in the diabetic group were decreased compared to those in control rats, but these were also fully restored to control levels by insulin therapy. However, plasma 1,25-dihydroxyvitamin D (1,25(OH)2D) levels in the untreated diabetic group tended to be lower than in controls, and the values in insulin-treated rats were significantly decreased compared to the control group. The ratio of 1,25(OH)2D to 25(OH)D in diabetic rats was higher than in controls, but it was decreased after insulin therapy and was significantly lower than in the control group. It is suggested, therefore, that the negative calcium balance and decreased 25(OH)D and 24,25(OH)2D levels are derived from the metabolic derangement due to the insulin deficiency. Furthermore, insulin seems to suppress the conversion of 25(OH)D to 1,25(OH)2D in experimental diabetes in vivo.

Animals↗
PubMed1984

Effects of environmental tobacco smoke on urinary cotinine excretion in nonsmokers. Evidence for passive smoking.

Despite recognition of the deleterious effects of passive smoking, quantitative information on the intake of environmental tobacco smoke is still lacking. Cotinine is the major metabolite of nicotine found in the urine. We have examined the relationship between urinary cotinine excretion in 472 nonsmokers and the smokiness of their environment. The urinary cotinine levels of nonsmokers who lived with smokers were higher than those of nonsmokers who did not, increasing with the combined daily cigarette consumption of smokers in the family. The urinary cotinine values of nonsmokers who worked with smokers were also higher than those of nonsmokers who did not, increasing with the number of smokers in the workroom. The presence of smokers in both the home and the workplace also increased the cotinine levels. Urban nonsmokers had more cotinine in their urine than rural nonsmokers. We conclude that the deleterious effects of passive smoking may occur in proportion to the exposure of nonsmokers to smokers in the home, the workplace, and the community.

Adult↗
PubMed1983

Effects of prostaglandin E2 and D2 on gastric somatostatin and gastrin secretion.

The effects of PGE2 and PGD2 on gastric somatostatin and gastrin releases were investigated using the isolated perfused rat stomach. In the presence of 5.5 mM glucose, the infusion of PGE2 elicited a significant augmentation in somatostatin release, but suppressed gastrin secretion from the perfusate. On the other hand, PGD2 did not affect somatostatin release, although the gastrin secretion decreased significantly, the same as after PGE2 infusion. These results suggest that PGE2 and PGD2 may be important in the regulation of gastric endocrine function, but that PGD2 does not affect gastric somatostatin secretion.

Animals↗
PubMed1983

Effect of tolbutamide on insulin, glucagon, and somatostatin release from the diabetic rat pancreas with special reference to glucose concentration.

The effects of tolbutamide on insulin, glucagon, and somatostatin secretion were investigated in the isolated perfused pancreas from normal and diabetic rats under low (30 mg/dl), normal (100 mg/dl), and high (300 mg/dl) glucose conditions. In the normal rat pancreas, tolbutamide-induced insulin release was increased when the glucose concentration in the perfusion medium was increased from 30-300 mg/dl. Tolbutamide had an inhibitory effect on glucagon release at the low (30 mg/dl) glucose concentrations, although a stimulatory effect was observed under normoglycemic conditions. The total amount of somatostatin secretion above baseline during tolbutamide infusion was higher under the normal glucose than under the low glucose condition. However, further augmentation of somatostatin release was not found at the high glucose concentration. In the diabetic rat pancreas, insulin release was diminished and tolbutamide-induced somatostatin release was enhanced with increasing glucose concentrations. Glucagon release was stimulated at the normal glucose concentration, but inhibited temporarily at the high glucose concentration. The maximum somatostatin response in the early phase was significantly decreased in the diabetic pancreas under low and normal glycemic conditions, when expressed as an incremental change (percentage) above baseline. From these results, one can conclude: (1) tolbutamide has a stimulatory effect on the pancreatic D cell in both the normal and diabetic pancreas; (2) the early response of somatostatin is decreased in the diabetic pancreas, except under conditions of high glucose concentration; and (3) the pancreatic A cell response to tolbutamide was not uniform and was quite different from the response of the D cell.

Animals↗
PubMed1983

Blood glucose and plasma insulin of mild diabetic patients in response to high protein divided meals.

To ascertain the effects on blood glucose and plasma insulin levels of divided meals in diabetes, we measured both plasma levels in mild diabetic patients and in normal subjects after a breakfast. Division of the breakfast into two portions of standard composition separated by 30 min improved blood glucose levels in diabetic patients considerably, but division in which the first portion was high in protein produced a blood glucose response almost identical to that of normal subjects. Division of the meal into two balanced portions also improved the insulin response similarly for diabetic patients, but division in which the first portion was high in protein improved it so markedly that it brought the diabetic insulin response almost in line with the insulin response of the normal controls. We conclude, therefore, that the best meal for mild diabetic patients is a divided meal with the first portion containing as much protein as practicable.

Adult↗
PubMed1982

Endocrine function of pancreas transplant: insulin, glucagon and somatostatin release from rat pancreatic isograft.

Using the whole pancreas transplantation model, we investigated the endocrine function of the isografted pancreatic A, B and D cells. The release of insulin, glucagon and somatostatin by the pancreatic grafts were examined and compared with those in normal rats with or without syngenic pancreas transplantation, using in vivo and in vitro systems. These studies demonstrate that the grafted pancreas maintained normal insulin, glucagon and somatostatin secretion after transplantation. This pancreatic graft may serve as a suitable experimental model for the studies on therapy for diabetes mellitus.

Animals↗
PubMed1982

Effect of long term bromocriptine treatment on glucose intolerance in acromegaly.

Blood glucose, plasma GH, insulin and glucagon levels during oral glucose tolerance test before and after treatment with bromocriptine (5-20 mg daily for 2-9 months) were investigated in eleven acromegalic patients with glucose intolerance. Nine out of 11 patients showed improvement or normalization in glucose tolerance after bromocriptine therapy. Basal levels of plasma GH were markedly decreased in 7 of 11 patients treated, although the improved glucose tolerance was not always associated with a drop of basal plasma GH levels. In contrast, basal plasma glucagon level showed a distinct fall in all the patients whose glucose tolerance was improved, but unchanged in whom glucose tolerance was not ameliorated. The mean values of plasma GH and glucagon after oral glucose load were significantly lower during bromocriptine therapy than those before the treatment, respectively. Basal levels of plasma insulin and its response to glucose load did not change after bromocriptine treatment. Bromocriptine thus appears to be a good alternative in the treatment of glucose intolerance in acromegalic patients and the improvement of glucose tolerance by bromocriptine may be related to the reduction in plasma glucagon levels. The possibility, however, is not excluded that a decrease by bromocriptine in the total daily GH secretion is a cause of the improved glucose tolerance.

Acromegaly↗
PubMed1982

Tolbutamide stimulates gastric somatostatin release from isolated perfused rat stomach.

The effect of tolbutamide on somatostatin release from the isolated perfused stomach was investigated in both normal and streptozotocin-diabetic rats. Tolbutamide (10, 100, and 1000 microgram/ml) evoked a significant and dose-dependent increase in gastric somatostatin release. The tolbutamide (100 microgram/ml)-induced gastric somatostatin secretion was not influenced by differences in glucose concentration (1.5, 5.5, and 16.5 mM) throughout the perfusion period. Tolbutamide (100 microgram/ml)-induced gastric somatostatin release in streptozotocin-diabetic rats was significantly higher than in normal rats. Thus, tolbutamide is a potent secretagogue for gastric somatostatin secretion, and this effect is more prominent in diabetic animals.

Animals↗
PubMed1981

Somatostatin in human pancreatic and gastric juice.

Considerable amounts of IRS are secreted after secretin injection in human pancreatic juice collected during endoscopic retrograde cholangiopancreatography. The mean IRS levels in the pancreatic juice of non-diabetic patients were 79 +/- 10 (SE) pg/ml. The IRS levels in NIDDM were considerably higher, the mean value being 1635 +/- 313 (SE) pg/ml. The mean IRS level in IDDM were 312 +/- 151 (SE) pg/ml. In IDDM, those patients whose blood glucose levels were well controlled by insulin showed low pancreatic juice IRS ranging from non-detectable to 46 pg/ml. On the other hand, those with uncontrolled hyperglycemia showed IRS levels ranging form 452 to 1047 pg/ml. Gel-filtration profiles of IRS in pancreatic juice extracts were not consistent in all cases. Some showed IRS peaks eluting with SS14 and SS28, while others contained IRS species that were eluted in more retarded fractions. The retarded IRS fraction exhibited biological activity indistinguishable from that of SS14 as indexed using a quantitative cytochemical method.

Chromatography, Gel↗