H.C. Dollinger

Effects of Somatostatin on Gastric Secretion and Gastrin Release in Man

Somatostatin, a recently synthesized hypothalamic growth hormone release-inhibiting factor (GIF), was used in the cyclic and linear form. In all subjects studied, the cyclic GIF inhibited gastrin secretion during basal conditions as well as during a standard food stimulus, with immediate rebound after the infusion was stopped. Similar responses were observed in a hypophysectomized patient, indicating that this effect of GIF was independent of suppression of growth hormone secretion. Cyclic and linear GIF, when administered in normal subjects during an infusion of synthetic human gastrin I, almost totally suppressed gastric secretion. The results indicate that GIF is a potent inhibitor of gastric secretion and gastrin release.

Differences in insulin, growth hormone and pancreatic enzyme secretion after intravenous and intraduodenal administration of mixed amino acids in man.

Abstract To determine whether intestinal hormones have a physiologic role in amino-acid-induced secretion of insulin, growth hormone and pancreatic enzymes, 42 metabolically normal human subjects were studied. An amino acid mixture (30 g) was administered intravenously and intraduodenally. A higher rise in serum insulin occurred after the intraduodenal application, and took place before the maximum blood concentration of amino acids was reached. Blood sugar, nonesterified fatty acids and free glycerol concentrations fell more clearly after intraduodenal administration. The route of administration did not significantly affect blood concentrations of growth hormone. After intraduodenal amino acids, the volume and bicarbonate contents of the duodenal juice rose slightly, whereas trypsin and bilirubin content increased considerably. These results suggest that, after oral administration of amino acids in man, only the secretion of insulin is clearly influenced by intestinal factors. Much evidence suggests that...

Hypergastrinemia induced by glucocorticoid and corticotropin treatment in man

To elucidate further the pathogenesis of steroid-induced ulceration, plasma gastrin levels, both basal and after a test meal, were studied in normal volunteers and patients treated with glucocorticoids or corticotropin. In normal subjects the acute intravenous administration of 100 mg prednisolone had no effect on plasma gastrin levels. After oral administration of predinisolone (40 mg daily, for four days) a significant increase of the basal, the reactive, and the over 90-min integrated gastrin release was observed. In this group, the glucocorticoid treatment had a slight, but significant influence on gastric acid and pepsin secretion, while acidity and pepsin output stimulated by pentagastrin was not affected. In patients treated with prednisolone for more than 24 weeks, the oral administration of this hormone failed to alter basal gastrin values but affected significantly secretion after the test meal. In patients with multiple sclerosis, after intramuscular administration of corticotropin (60 IU daily, for 12 days), an increase of the basal, the reactive, and the integrated gastrin release also was found. Glucocorticoid-induced hypergastrinemia provides information on the pathogenesis of steroid-induced ulceration.

Effects of Secretin and Cholecystokinin on Motor Activity of Human Jejunum

The effects of intravenous administration of secretin and cholecystokinin (CCK) on motility of the human jejunum were investigated with pressure-sensitive radiotelemetering capsules. Secretin inhibited and CCK stimulated the spontaneous motor activity of this part of the small intestine. Raising the dosages of the two hormones caused increasing effects. It seems likely, therefore, that both hormones play a role in the regulation of intestinal motility in man.

The Effect of the β-Receptor Blockade (Propranolol) on the Endocrine and Exocrine Pancreatic Function in Man after the Administration of Intestinal Hormones (Secretin and Cholecystokinin-Pancreozymin)

Abstract. The effect of propranolol on the induction of endocrine and exocrine pancreatic function by secretin (SC) and cholecystokinin‐pancreozymin (CCK/PZ) was investigated in 35 metabolically normal subjects. Insulin secretion could be inhibited by propranolol after administration of glucose or SC. On the other hand it was not possible to inhibit the CCK/ P2 induced insulin secretion by propranolol. Exocrine pancreatic function was not influenced by the administration of propranolol. Our results suggest that the action of SC on the islet system, like that of glucose, is linked to the β‐adrenergic system.

Influence of Ethanol, Caffeine and Intragastric Cooling on Gastrin and Insulin Secretion in Man

In man, oral administration of coffee (277 mg caffeine) caused a striking increase in gastrin secretion, as measured by radioimmunoassay. The radioimmunologically measurable insulin and blood glucose

The influence of l-(5-oxohexyl-)3.7-dimethylxanthine (BL 191) on the endocrine and exocrine pancreatic function in man during and following secretin and cholecystokinin-pancreozymin stimulation

SummaryThe intravenous administration of secretin or cholecystokinin-pancreozymin alone led to a short rapid rise in radio-immunologically measurable insulin, and to a stimulation of the hydrokinetic as well as the ecbolic, exocrine pancreatic function.During the administration of 1-(5-oxohexyl-)-3.7-dimethylxanthine (BL 191) no significant change in the endocrine and exocrine pancreatic secretion was registered, compared to the secretin injection alone, whereas BL 191 was able to inhibit the insulin and enzyme secretion after the administration of cholecystokinin-pancreozymin.The influence neither of secretin nor cholecystokinin-pancreozymin on the endocrine as well as the exocrine pancreas seems to be mediated directly by cyclic 3′-5′ adenosine monophosphate (cAMP), and the decrease of endocrine and exocrine pancreatic secretion, induced by cholecystokinin-pancreozymin during administration of BL 191, is probably due to an inhibition of the alpha-receptor system. Additional experiments are required for further elucidation of these conclusions.

Effects of secretin and cholecystokinin-pancreocymin on water, electrolyte and glucose absorption in human jejunum: A Comparison Between Different Hormone Preparations

SummaryThe effects of natural secretin (90%) and synthetic secretin as well as impure (10%) and pure (99%) cholecystokinin-pancreozymin (CCK) on net absorption of water, electrolytes, and glucose in human jejunum were studied in 31 normal subjects. An intestinal perfusion technique with a triple-lumen tube was used. Net absorption of water and solute was significantly inhibited by both hormones only with larger doses, pure CCK being less active than impure CCK. A dose-dependent response of water and electrolyte absorption to graded doses of pure CCK was observed, without concomitant inhibition of glucose absorption with lower doses. The findings suggest that secretin and CCK may not be of physiologic importance regarding intestinal absorption in man. The definite changes in intestinal motility and transit rate caused by these hormones seem more likely to result in a reduction of intestinal absorption and an increase in the secretion of water and electrolytes along the proximal small bowel.

Gastrin release and gastric secretion induced by dimethylxanthine in man

SummaryGastrin release and gastric secretion in response to i.v. dimethylxanthine (2 mg/kg for 5 min followed by a 55-min infusion of 2.5 mg/kg) were studied in 25 normal subjects. Gastrin release was significantly stimulated, whereas gastric acid and pepsin secretion was inhibited. The adenylcyclase activation may, therefore, play a role in the mechanism of gastrin release. Moreover, dimethylxanthine seems to be a useful aid in studies on G-cell function in man.

Effect of Lipids on Insulin, Growth Hormone and Exocrine Pancreatic Secretion in Man*

Abstract. Influences of fat on release of insulin, growth hormone and pancreatic enzyme secretion were studied in 35 metabolically healthy subjects. A fat solution containing 40 g of soy bean oil was administered, I. V., orally and intraduodenally. In all cases there was a similar increase of insulin but the rise in serum insulin after oral or intraduodenal fat administration was not related to the changes in plasma free fatty acids, free glycerol and triglyceride levels. Blood sugar responded according to insulin secretion. The route of fat administration may possibly influence growth hormone secretion. Following intraduodenal fat administration volume and bicarbonate contents of the duodenal juice rose slightly whereas trypsin and bilirubin content increased considerably. These results suggest that insulin secretion after oral or intraduodenal administration of fat is influenced by intestinal factors. Cholecystokinin‐pancreozymin and gastric inhibitory polypeptide are qualified to serve as such factors.