14102 studies
We present evidence for a new mechanism by which two major actin monomer binding proteins, thymosin beta 4 and profilin, may control the rate and the extent of actin polymerization in cells. Both proteins bind actin monomers transiently with a stoich…
Molt induced by infusion of a gonadotropin-releasing hormone agonist (GnRH-A, ([D-leu6,Pro9]-GnRH N-ethylamide]) or feed withdrawal (FW) has been used as a model to study interactions between ovarian activity and thymosin beta 4 during molting in dom…
Thymosin beta 4 (T beta 4), a 5-kD peptide which binds G-actin and inhibits its polymerization (Safer, D., M. Elzinga, and V. T. Nachmias. 1991. J. Biol. Chem. 266:4029-4032), appears to be the major G-actin sequestering protein in human PMNs. In sup…
The actin binding sites of actobindin and thymosin beta 4, two small polypeptides that inhibit actin polymerization by interacting with monomeric actin, have been localized using peptide mimetics. Both sites are functionally similar and extend over 2…
The effects of synthetic thymosin peptides (T alpha 1 and T beta 4) and their antibodies on the fertilizing capacity of human sperm cells were investigated. T alpha 1, but not the T beta 4, significantly (p < 0.001) increased the human sperm penetrat…
To elucidate any mechanism of a body protecting effect the observed events should be investigated also by the way of their modulations induced by ablation of particular organs. For Body Protection Compound (BPC), a newly partially characterized gastr…
The biosynthesis of serotonin into melatonin was decreased in old (18-20-month) in comparison to young (4-5-month) male Wistar rats. 5-day morning injections to young and old rats with polypeptide pineal preparation (epithalamin) in a dose of 2.5 mg/…
The aim of our study was to investigate the effects of aging on the growth hormone (GH) response to growth hormone-releasing hormone (GHRH) alone and in combination with either the neuropeptide galanin or the acetylcholinesterase inhibitor pyridostig…
Experimental evidence indicates that the neonatal gonadal steroid environment is an important determinant of the sexual dimorphism of GH secretion and body growth. However, the influence of the sex steroids in GH control during adult life and their m…
Recent studies have suggested that growth hormone-releasing factor (GRF), like vasoactive intestinal peptide (VIP), may enhance follicle-stimulating hormone (FSH)-stimulated steroidogenesis in cultured rat granulosa cells (GC). Because effects of GRF…
We have evaluated the effect of acute administration of atenolol, a selective beta-adrenergic antagonist, on the GH response to GHRH in nine obese children and in eight age-matched controls. The GH response to GHRH (1-29, 1 microgram/kg iv), evaluate…
GH secretion has been thought traditionally to be regulated by the two hypothalamic hormones, GH-releasing hormone (GHRH) and somatostatin (SRIF). Recent evidence has suggested that other factors may be involved. These factors include the natural lig…
This study examined whether maneuvers that chronically raise or lower serum insulin-like growth factor I (IGF-I), within physiological and pathophysiological ranges, will affect glomerular hemodynamics. Pair-fed Munich Wistar rats received, for 6 to…
Effects of growth hormone-releasing factor (GRF) on energy and N metabolism in six growing Hereford x Angus steers were measured using a split-plot design with 4-wk injection periods within 8-wk intake periods. Steers were fed a 75% concentrate pelle…
Exogenous GH is known to exert a negative feedback effect on its own responsiveness to GH-releasing factor (GRF); however, the mechanism is not known. In the present study we examined the time course of effects of a single sc administration of recomb…
An involvement of neurogenic components in the pathogenesis of psoriatic lesions has been suggested and neuropeptides are thought to play a modulatory role in cutaneous inflammation. In this study, we evaluated the immunoreactivity of the neuropeptid…
Products of the degradation of human growth hormone-releasing factor (GRF) in aqueous solutions (15-200 microM) have been isolated and fully characterized. The cleavage product, GRF(4-44)-NH2, and the isomerization product, [beta-Asp3]GRF(1-44)-NH2,…
Average growth hormone (GH) peaks following an i.v. growth hormone releasing hormone (GHRH) 1-29 stimulation test were significantly lower in 48 children and adolescents with GH deficiency (GHD) than in 20 age-matched controls (15.2 + 12.7 vs 37.5 +…
Two experiments were conducted to determine the effects of immunoneutralization of growth hormone-releasing factor [GRF(1-29)-NH2] on concentrations of somatotropin (ST) and insulin-like growth factor I (IGF-I) in lactating beef cows. In Experiment 1…