14102 studies
This study examined the effects of chronic deletion of circulating growth hormone-releasing (GHRH) and/or somatostatin (SRIF) on normal growing male rats, as well as the effects of exogenous GHRH (1-29)NH2 and/or SMS 201-995 administration on the gro…
The purpose of this investigation was to characterize the nature of peptide histidine isoleucine (PHI) and vasoactive intestinal polypeptide (VIP) receptors, and to examine the role of PHI in internal anal sphincter (IAS) relaxation. The studies were…
Seven children with growth hormone deficiency of hypothalamic origin responded to an i.v. bolus of growth hormone releasing hormone (GHRH) (1-29)-NH2 with a mean serum increase of 10.7 ng/ml growth hormone (GH) (range 2.5-29.3 ng/ml). Continuous s.c.…
The response to GH releasing hormone (GHRH 1-29) and 24-h serum GH and IGF-I levels were measured in 9 insulin-dependent diabetics with retinopathy and 6 normal volunteers before and after different treatment regimens with octreotide, a long-acting s…
We previously reported that systemic administration of the recently described GRF peptide antagonist (N-Ac-Tyr1,D-Arg2)GRF-(1-29)-NH2 to adult male rats would suppress the pulsatile release of GH. In the present study, we have sought to determine whe…
Microinjection of synthetic GRF into the cerebroventricles or hypothalamus of the rat produces a number of neural effects, including the suppression of GH secretion, possibly representing a negative ultrashort loop autoregulation of GRF and/or stimul…
1. The effects of several drugs, including antagonists of vasoactive intestinal peptide (VIP), and antisera to VIP or peptide histidine isoleucine (PHI), on relaxation responses of guinea-pig isolated trachea to electrical field stimulation (EFS) hav…
Guinea-pig vasoactive intestinal peptide (gpVIP-(1-28] in the concentration range 3 x 10(-9)-3 x 10(-7) mol.1-1 relaxed precontracted segments of the guinea-pig uterine artery. Porcine VIP-(10-28) (pVIP-(10-28], [4-Cl-D-Phe6,Leu17]VIP, or [N-Ac-Tyr1,…
Hypothalamic-pituitary function was studied in four children with Optic Nerve Hypoplasia (ONH). All were found to be growth hormone deficient when provoked with glucagon or insulin induced hypoglycaemia (ITT), but did respond to bolus injection of GH…
His-D-Trp-Ala-Trp-D-Phe-Lys-NH2 (GHRP-6) stimulated GH release from rat primary pituitary cells in a time- and dose-dependent manner. Stimulation was observed after a 15-min, but not a 4-h, incubation. The concentrations of GHRP-6 required for half-m…
Studies in man demonstrated that intramuscular salmon (s) calcitonin (CT) administration blunted pituitary GH response to hypothalamic stimuli such as arginine infusion and insulin-induced hypoglycaemia. However, the mechanisms underlying this inhibi…
An experiment was conducted to determine the effects of exogenously administered FFA on GH and LH secretion in sheep. Ovariectomized ewes received iv infusions of a mixture of FFA (166 mg/min; n = 5) or 0.9% saline (n = 4) for 10 h. Jugular blood was…
Endogenous GH secretion was measured every 20 min for 24 h in 36 short children. This was immediately followed by an i.v. injection of GH-releasing hormone (GHRH)(1-29)-NH2 (1 microgram/kg), and GH was estimated every 15 min for the following 2 h. Th…
A bovine growth hormone-releasing factor analog, Leu27-bGRF(1-29)NH2, was rapidly hydrolyzed to Leu27-bGRF(3-29)NH2 when incubated at 0.03 mM with porcine and bovine plasma at 37 degrees C in vitro (t1/2 = 8.4 min and 22.1 min, respectively). The sit…
The Met-enkephalin analog DAMME [D-Ala2,MePhe4-Met-enkephalin-(o)-o1, FK 33-824] can stimulate GH secretion in man. In this study we investigated the effects of the guanyl derivative of DAMME (G-DAMME) on the serum GH response to an analog of GHRH in…
In mammals including human, it is generally accepted that growth hormone (GH) can regulate its own secretion through an autofeedback mechanism in which somatostatin (SRIF) may be involved. To explore a physiological role of SRIF-mediated GH autoregul…
Three experiments were conducted with growing pigs actively immunized against a protein-conjugated somatostatin (SRIF) in Freund's adjuvant. In the first experiment, blood from 24-week-old pigs (seven immunized and eight control) was sampled at 20-mi…
Vasoactive intestinal polypeptide (VIP), peptide histidine isoleucine (PHI), and helodermin stimulate electrogenic anion secretion in preparations of rat jejunum stripped of muscularis propria. Concentration-response curves to exogenously applied pep…
The effects of a long term treatment with human GRF(1-29)NH2 on plasma growth hormone (GH), somatomedin C (Sm-C), histomorphometric parameters of bone growth and body composition were investigated in normal and low birthweight male lambs. The animals…
Fourteen patients with pituitary lesions and 6 normal subjects underwent the following tests: a) LHRH (100 mcg) + TRH (200 mcg) + Human Insulin (0.1 UI/kg) i.v. (Politest "A"); b) LHRH (100 mcg) + TRH (200 mcg) + GHRH 1-29NH2 (100 mcg) i.v. (Politest…