Studies

Relaxations of the feline intrapulmonary bronchus (IPB) induced by VIP or nonadrenergic noncholinergic (NANC) inhibitory nervous stimulation were unaffected by the VIP receptor antagonist [Ac-Tyr1,D-Phe2]-GRF (1-29) (30 microM). A second VIP antagoni…

The nature of the inhibitory neurotransmitter responsible for internal anal sphincter (IAS) relaxation in response to rectoanal reflex is not known. The objective of the present investigation was to examine the role of VIP in IAS relaxation in respon…

The effects of 8 day continuous subcutaneous (s.c.) infusions of growth hormone releasing hormone analogue (NLE27GRF(1-29)NH2 (GHRH.A)) on growth hormone (GH) secretion were studied in 14 normal adult male volunteers. GHRH.A was administered in doses…

Vasoactive intestinal peptide (VIP)-immunoreactive nerve fibers have been demonstrated in the rat adrenal cortex in close association with zona glomerulosa cells, suggesting neural regulation of adrenocortical cell function (5). The present studies w…

Sixteen prepubertal children who were insufficient for growth hormone were treated with growth hormone releasing hormone (GHRH) 1-40 and GHRH 1-29 for a mean time of nine months (range 6-12 months) with each peptide. Eleven children received GHRH 1-4…

The effects of iv administration of growth hormone-releasing factor (GRF) on growth hormone (GH) release and on nitrogen metabolism were measured in prepubertal calves. Crossbred beef heifers (111 kg) were used in a Latin square design to test the ef…

Biological potencies of three 29 amino acid growth hormone-releasing hormone analogs (GHRH[1-29]) were determined in the bovine and compared to synthetic human GHRH (44 amino acids; hGHRH[1-44]NH2) for their ability to increase serum growth hormone (…

Analogs of growth hormone-releasing factor-(1-29)-NH2 (GRF-29) involving derivatization with alkyl substituents at the N-terminus, with or without concomitant alkylation of basic amino acids within the peptide chain (lysine in positions 12 and 21), w…

1. The effects of two specific antagonists of vasoactive intestinal peptide (VIP) receptors were investigated on the VIP-induced hyperpolarization of the membrane potential of the Schwann cell of the giant nerve fibre of the tropical squid. 2. Both (…

Recently, we have developed a long-acting delivery system for our somatostatin (SS) analog RC-160 based on injectable microcapsules in poly-(D,L-lactide-coglycolide). We studied the capacity of this formulation to repeatedly block the GH secretion in…

The negative-feedback effects of GH on its own secretion were studied in conscious male and female rats bearing indwelling double-bore venous cannulae. Intravenous infusions of human GH (hGH; 20-60 micrograms/h) or somatostatin (SS; 10 micrograms/h)…

Osmotic pumps were evaluated for 7-d delivery of growth hormone-releasing factor (GRF). In Exp. 1, 12 steers weighing 253 kg received hGRF(1-29)NH2 in H2O at rates of 0, 3, 30 and 300 pmol.h-1.kg-1. Pumps were implanted s.c. on d 0 and removed at 120…

To determine whether human calcitonin inhibits GH secretion in man, as has been described for salmon calcitonin, the effect of an i.v. bolus of human calcitonin or saline on GH release after either insulin-induced hypoglycaemia or the administration…

A novel cyclic GRF analog, cyclo(Asp8-Lys12)-[Asp8,Ala15]-GRF(1-29)-NH2, i.e. cyclo8,12[Asp8,Ala15]-GRF(1-29)-NH2, was synthesized by the solid phase procedure and found to retain significant biological activity. Solid phase cyclization of Asp8 to Ly…

Sequences of seven tryptic peptides derived from Saccharomyces cerevisiae glutamine synthetase have been determined. The amino terminus of yeast enzyme is acetylated and has the following sequence: acetyl-Ala-Glu-Ala-Ser-Ile-Glu-Lys. Neither higher e…

Barnacle pheromone enhances the rate of settlement and metamorphosis of larvae of Balanus amphitrite Darwin. Analogs to the heterogenous pheromone peptides were sought. Settlement assays were used to assess both the pheromone and the potential analog…