The central and renal hemodynamic effects of amino acid infusion in the study of renal reserve in the baboon.

Normal human renal function is characterized by a large renal reserve. Recruitment of this reserve is a compensatory and pathological response to renal injury. This study was designed to assess the renal reserve and central hemodynamics of young female baboons and, in doing so, the appropriateness of the use of these animals in a model of human renal disease.

Endogenous somatostatin-28 modulates postprandial insulin secretion. Immunoneutralization studies in baboons.

Somatostatin-28 (S-28), secreted into the circulation from enterocytes after food, and S-14, released mainly from gastric and pancreatic D cells and enteric neurons, inhibit peripheral cellular functions. We hypothesized that S-28 is a humoral regulator of pancreatic B cell function during nutrient absorption. Consistent with this postulate, we observed in baboons a two to threefold increase in portal and peripheral levels of S-28 after meals, with minimal changes in S-14.

Evidence that galanin is a parasympathetic, rather than a sympathetic, neurotransmitter in the baboon pancreas.

To determine whether galanin is a pancreatic sympathetic neurotransmitter regulating insulin secretion in the baboon, as it is in the dog, we evaluated galanin for inhibitory effects on insulin secretion in conscious baboons, determined if baboon pancreatic islets are innervated by galaninergic fibers using immunohistochemistry, and measured galanin content in the major sympathetic ganglion supplying the pancreas. Surprisingly, infusion of galanin (1 microgram/kg per min) had no effect on arginine-stimulated secretion of either insulin (71 +/- 14 vs. 88 +/- 17 microU/ml; P = NS) or glucagon (104 +/- 12 vs.

Elimination of the action of glucagon-like peptide 1 causes an impairment of glucose tolerance after nutrient ingestion by healthy baboons.

Glucagon-like peptide 1 (GLP-1) is an insulinotropic hormone released after nutrient ingestion which is known to augment insulin secretion, inhibit glucagon release, and promote insulin-independent glucose disposition. To determine the overall effect of GLP-1 on glucose disposition after a meal we studied a group of healthy, conscious baboons before and after intragastric glucose administration during infusions of saline, and two treatments to eliminate the action of GLP-1: (a) exendin-[9-39] (Ex-9), a peptide receptor antagonist of GLP-1; or (b) an anti-GLP-1 mAb. Fasting concentrations of glucose were higher during infusion of Ex-9 than during saline (4.

Estradiol inhibits the increase of hypothalamic neuropeptide Y messenger ribonucleic acid expression induced by weight loss in ovariectomized rats.

Anorexia and weight loss produced by estradiol (E2) may involve altered expression of neuropeptide Y (NPY) in the hypothalamus. We tested this hypothesis using ovariectomized (OVX) rats by replacing E2 with SILASTIC brand capsule implants and measuring NPY messenger RNA (mRNA) levels in the arcuate nucleus by in situ hybridization. To equalize the effects of weight loss on NPY mRNA expression, E2 deficient OVX rats were pair-fed (n = 10) for 2 days to an OVX group receiving E2 (n = 12).