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Biomedical subjects

E F Pfeiffer

Publications and source records attributed to E F Pfeiffer.

At least 181 records · Page 10Linked to original sources
PubMed1982

Effect of acetylcholine on the release of pancreatic and gastric somatostatin-like immunoreactivity in normal, chemically sympathectomized and indomethacin-treated dogs.

The present study was designed to determine the effects of intravenously infused acetylcholine on the release of pancreatic and gastric somatostatin-like immunoreactivity (SLI), in anesthetized normal, chemically sympathectomized and Indomethacin-treated prostaglandin deficient dogs. In normal dogs acetylcholine infusion (500 micrograms/min) elicited a significant rise in pancreatic vein, inferior vena cava, fundic and antral vein SLI levels. In the sympathectomized animals the rise in pancreatic and antral vein SLI was not different from the controls, while the rise in fundic vein SLI was abolished, and inferior vena cava plasma SLI levels were reduced. During Indomethacin-induced prostaglandin deficiency, basal SLI levels were reduced significantly, and the acetylcholine-induced stimulation was completely abolished from both stomach and pancreas. It is concluded that in anesthetized dogs the intravenous infusion of acetylcholine stimulates pancreatic and gastric SLI release, and this stimulatory effect depends on the presence of prostaglandins and is modulated by adrenergic mechanisms.

Acetylcholine↗
PubMed1981

[T3-hyperthyroidism under the aspects of secretion and peripheral production of thyroid hormones (author's transl)].

In contrast to T4/T3-hyperthyroidism, where T4, T3, and r-T3 serum concentrations (SC) are elevated, in T3-hyperthyroidism the T3-SC alone is increased, whereas T4-SC is normal and r-T3 may be decreased. Endogenous labelling of T4 with 131I is increased in T3-hyperthyroidism similarly as in T4/T3-hyperthyroidism, clearly reflecting an increased thyroidal formation of T4 in T3-hyperthyroidism. The contradiction of a normal SC to T4 in the presence of enhanced thyroidal formation of T4 may be explained by increased peripheral T4-deiodination. Since in T3-hyperthyroidism T3-SC are elevated whereas r-T3-SC are decreased, there is good evidence for a shift in T4 conversion.

Humans↗
PubMed1981

Effect of physiological increments of blood glucose on plasma somatostatin and pancreatic polypeptide levels in dogs.

The present study was designed to determine the effects of physiological increments of plasma glucose levels upon basal and stimulated plasma somatostatin and pancreatic polypeptide levels. In seven conscious dogs the elevation of plasma glucose levels by 30-40 mg/dl did not change basal somatostatin and pancreatic polypeptide levels. During stimulation of these two hormones by acetylcholine and the octapeptide of cholecystokinin intravenous infusion of glucose elicited a significant decrease of somatostatin levels by 30 pg/ml and of pancreatic polypeptide levels by 300 pg/ml. The present data demonstrate that a physiological elevation of plasma glucose levels inhibits stimulated but not basal somatostatin and pancreatic polypeptide levels which may be of importance for nutrient entry and metabolism.

Acetylcholine↗
PubMed1981

Effect of solid and liquid carbohydrates upon postprandial pancreatic endocrine function.

The present study was designed to determine the effect of sucrose-containing liquids upon postprandial pancreatic endocrine function in comparison to an identical quantity of sucrose contained in the solid part of the test meal. In 10 normal subjects, the ingestion of a solid-liquid meal with sucrose in the liquid part elicited a significantly greater increase in the plasma insulin and glucose levels during the first 20 min than did the ingestion of the same meal in homogenized form. Plasma glucagon levels fell below baseline during the early phase of the meal in response to the solid-liquid meal, whereas values increased immediately upon ingestion of the homogenized meal. To determine the effect of repeated ingestion of sucrose-containing liquids, 6 subjects ingested a meal containing sucrose in solid form together with water (solid sucrose); on another occasion, the same subjects ingested the sucrose in liquid form. In response to the liquid-sucrose meal, mean postprandial plasma insulin levels were significantly higher than those observed in response to the solid-sucrose meal (110 +/- 11.3 vs. 80 +/- 8.5 microunits/ml; P less than 0.01) as were plasma glucagon levels (284 +/- 12.2 vs. 198 +/- 8.2 pg/ml; P less than 0.001). Mean postprandial plasma glucose levels and the insulin to glucagon ratio were not different. The present data demonstrate that the ingestion of sucrose in the liquid part of a meal results in a significant elevation of plasma insulin concentrations compared to the ingestion of sucrose in the solid part of the meal.

Adult↗
PubMed1981

Evidence for an effect of exorphins on plasma insulin and glucagon levels in dogs.

Recently, peptides with opioid-like activity have been demonstrated in peptic digests of dietary protein. The present study was designed to determine the effect of digested and undigested gluten on postprandial insulin and glucagon levels in conscious dogs. The intragastric instillation of digested gluten (25 g) elicited a more rapid and a significantly greater rise in postprandial peripheral vein insulin and glucagon levels compared with the effect of 25 g undigested gluten. The incremental insulin level was 104 +/- 20 microU/ml after digested gluten and only 58 +/- 7 microU/ml (P less than 0.01) after undigested gluten; the respective values for glucagon are 426 +/- 25 pg/ml versus 302 +/- 20 pg/ml (P less than 0.01). The intragastric administration of naloxone (4 mg), a specific opiate receptor antagonist, reduced the insulin response and augmented the glucagon response to the digested gluten test meal, whereas the response of both hormones to the undigested gluten meal was not affected by naloxone. Intravenously infused naloxone during the digested gluten meal did not influence insulin or glucagon levels. The present data suggest that in dogs the peptic digest of gluten contains an opioid-like material that stimulates postprandial insulin and glucagon release.

Animals↗
PubMed1981

[Determination of endogenous labelling of thyroid hormones during a radioiodide test in euthyroid goiter patients and hyperthyroid patients (author's transl)].

The administration of a diagnostic dose of radioiodide, as in the radioiodide uptake test, results in the formation and secretion of radioactive thyroid hormones (endogenous labelling). In this report a method is described by which thyroid hormones are chromatographically isolated from serum, with the simultaneous assessment of the incorporated radioactivity over a period of time. A low-level counter was used to measure the small amounts of activity present. By this method the hormone phases during a radioiodide uptake test may be better evaluated. The present results show a good diagnostic discrimination between euthyroidism and borderline or definite hyperthyroidism (by a factor of 10 and 40, respectively). The influence of factors such as a small intrathyroidal iodide pool need, or course, to be considered. Hence, by taking into account such parameters as the intrathyroidal iodide pool, the hormone clearance etc, a technique for the measurement of thyroid hormone secretion can be developed.

Goiter↗
PubMed1980

Effect of bombesin upon plasma somatostatin-like immunoreactivity, insulin and glucagon in normal and chemically sympathectomized dogs.

The present study was designed to determine the effects of intravenously infused bombesin (10 ng/kg/min) upon basal and postprandial plasma somatostatin-like immunoreactivity (SLI), glucagon, insulin and triglyceride levels in normal (n = 12) and chemically sympathectomized (n = 11) dogs. Basal plasma SLI, glucagon and insulin levels rose significantly during the infusion of bombesin in the normal dogs, and this was not altered by chemical sympathectomy. Bombesin infusion enhanced the postprandial SLI response, while attenuating the postprandial glucagon response by 50% and the insulin response in the early postprandial phase of the meal. Sympathectomy did not significantly alter the basal levels of these polypeptides, but augmented the postprandial plasma SLI response during the first 90 min, and reduced the postprandial glucagon response during the infusion of bombesin. The postprandial insulin response was not affected by sympathectomy. In both normal and chemically sympathectomized dogs the rise in postprandial triglyceride levels was attenuated by bombesin infusion.

Animals↗
PubMed1980

Insulin biosynthesis and release in isolated islets from hyperglycemic male rats.

Normal male rats were made hyperglycemic for 24 hours by the infusion of high amounts of glucose and the effect of mannose, glucose and glucose plus glucagon on insulin biosynthesis and release was studied in the isolated islets. Saline infused animals served as controls. It was found that all stimuli markedly enhanced the pro-/insulin biosynthesis in islets from hyperglycemic rats in comparison with saline infused animals. Maximal insulin release was observed in the control group with 300 mg/dl glucose plus 10 microgram/ml glucagon, while submaximal stimulation with 100 mg/dl mannose or glucose resulted in a higher insulin secretion rate in B-cells from hyperglycemic animals at 60 min, when compared with the saline infused animals. The results show that elevation of the blood glucose results in an overall stimulation of insulin biosynthesis and secretion, while lowering of the blood sugar as in starvation predominantly decreases the glucose dependent mechanisms for both insulin synthesis and release.

Animals↗
PubMed1980

Islet transplantation in experimental diabetes of the rat. VII. Cryopreservation of rat and human islets. Preliminary results.

Islet transplantation in human diabetes at present is confronted with two major obstacles: isolation of a sufficient number of islets and islet graft rejection. "Tissue banking" would enable islet pooling from various donors and offers furthermore the advantage of in vitro manipulations in order to reduce islet immunogenicity. Recently we have reported successful cryopreservation and subsequent transplantation of porcine islets (Bretzel, Beule, Schäfer, Schneider, Pfeiffer and Federlin 1979). These preliminary data deal with cryopreservation and transplantation of isolated rat islets and cryopreservation of isolated human islets.

Animals↗