Hormonal and metabolic effects of somatostatin in diabetic patients submitted to an i.v. arginine infusion

Hormonal and metabolic effects of a synthetic linear somatostatin were tested in insulin-dependent subjects submitted to an intravenous arginine infusion. Arginine alone induced a rise in plasma growth hormone (HGH) and glucagon (IRG) concentrations but did not affect the spontaneous diurnal decrease of plasma cortisol; blood glucose concentration rose while that of alanine decreased suggesting enhanced gluconeogenesis; concentrations of plasma free fatty acids (FFA) and 3-hydroxybutyrate decreased. Somatostatin, at three different dosages, markedly influenced these patterns: HGH response to arginine was suppressed by the lowest somatostatin dose; IRG response was progressively inhibited by increasing doses of somatostatin but never reached zero; cortisol level was not decreased but slightly increased by somatostatin. Substrate responses to arginine were also modified by somatostatin: alanine disappearance was impaired, this effect being dose-related; plasma FFA and 3-hydroxybutyrate concentrations showed a significant increase rather than decrease, consistent with somatostatin suppression of residual insulin secretion. Tolerance to somatostatin was good and no alteration of hemostasis was observed.