The control of M-current by muscarinic ACh receptors and luteinizing hormone releasing hormone (LHRH) receptors was studied in dialyzed frog sympathetic ganglion neurons. M-current was recorded in dialyzed cells without run-down or changes in its biophysical properties and could be reversibly suppressed by muscarine and teleost LHRH (t-LHRH). However, dialysis with internal solutions lacking AT...

Hypophysial portal blood and peripheral blood were obtained from conscious, unrestrained rams to measure simultaneously the secretion of LHRH and LH in entire rams and rams which had been castrated for 2-15 days (short-term castration) and for 1-6 months (long-term castration). The apparatus for portal blood collection was surgically implanted using a transnasal trans-sphenoidal approach and, 4...

Nitric oxide (NO) affects reproductive processes both at the level of the brain and reproductive tract and this review is focused on its role as an essential regulator of the hypothalamic control of reproduction. The data gathered indicate that glutamate stimulates noradrenergic neurons which subsequently activate NO-ergic cells via alpha1-adrenergic receptors. The released NO diffuses into lut...

The vomeronasal system of mammals is a specialized chemosensory pathway that parallels the main olfactory system but is anatomically distinct from its peripheral aspect through its projections into the central nervous system.'.' Recent evidence suggests a predominant role for the vomeronasal system in conveying the influence of odor stimuli upon neuroendocrine and on a variety of motivated beha...

Changes in numbers of ovarian follicles and coincident secretion of pituitary gonadotropins were characterized in suckled, anovulatory beef cows injected iv with 500 ng of luteinizing hormone-releasing hormone (LHRH) every 2 h for 48 or 96 h, starting 21.4 +_ .4 d after parturition. Two hours after the last injection, all cows were ovariectomized. Compared with saline-injected controls, LHRH ha...

The requirements of purified rat Leydig cells for intra- and extra-cellular Ca2+ during steroidogenesis stimulated by LH (lutropin), cyclic AMP analogues and LHRH (luliberin) agonist were investigated. The intracellular Ca2+ concentrations ([Ca2+]i) were measured by using the fluorescent Ca2+ chelator quin-2. The basal [Ca2+]i was found to be 89.4 +/- 16.6 nM (mean +/- S.D., n = 25). LH, 8-brom...

Reproduction is adversely affected by alcohol abuse in humans and laboratory animals. In rats, alcohol exposure suppresses both luteinizing hormone (LH) and sex steroid secretion, although consensus is lacking as to which level of the hypothalamic-pituitary-gonadal (HPG) axis is primarily affected. We tested the hypothesis that acute alcohol treatment inhibits the HPG axis by blunting release o...

The purpose of this project is the investigation of LHRHa2 integrated effect with carp pituitary extract (CPE) in three stages injection on sexual indexes (fecundity, fertilization, hatch and larval survival) in artificial propagation of Barbusxanthopterus. 20 fish were divided in to 4 treatment and injected interpritoneal as follows 4mgkg-1b.w.of CPE as positive control, 4 µg/kg +4 mgkg-1b.w. ...