... of both FSH and LH, consistent with direct pituitary gonadotrope dysfunction. Patients with macroadenoma and extremes of serum gonadotropin values (either serum FSH or LH > 8 IU/L) were more likely to have NFPA than prolactinoma. Patients with PCOS and hyperprolactinaemia had LH-predominant secretion...

... in that it is characterized by enhanced FSH secretion and FSH responsiveness to exogenous GnRH (vs. LH) from the gonadotrope, yet the mechanism of these dynamics remains unclear. This study aimed to elucidate this phenomenon using a human disease model of GnRH deficiency (idiopathic hypogonadotropic hypogonadism, IHH...

...James L. O’Conner; Marlene F. Wade; Darrell W. Brann; Virendra B. Mahesh Neuropeptide Y (NPY) acts at the hypothalamus to stimulate LH secretion through increased LHRH secretion. NPY is also cosecreted into the portal system in a pulsatile manner with LHRH and may act at the anterior pituitary...

...Darrell W. Brann; Pedro L. Zamorano; Carla D. Putnam-Roberts; Virendra B. Mahesh Previous studies in the male rat have demonstrated that GABA acting via GABAB receptors can abolish naloxone-induced LH secretion. The purpose of the present study was to determine if an analogous situation exists...

...Hubertus Jarry; Burkhard Hirsch; Sabine Leonhardt; Wolfgang Wuttke To investigate the role of amino acid neurotransmitters in the regulation of LH secretion in ovariectomized (ovx) rats with or without estrogen substitution, we measured the release rates of γ-aminobutyric acid (GABA), taurine...

...Sharada Karanth; Umeko Marubayashi; Samuel M. McCann Interleukin-2 (IL-2) alters the release of anterior pituitary hormones at femtomolar concentrations from hemipituitaries incubated in vitro. This cytokine significantly lowered luteinizing hormone (LH) and follicle-stimulating hormone (FSH...

...Ruth I. Wood; Helen I’Anson; Francis J.P. Ebling; Douglas L. Foster The sheep exhibits a marked sex difference in the timing of the pubertal increase in luteinizing hormone (LH). Male lambs undergo a reduction in sensitivity to inhibitory steroid feedback, leading to an increase in LH by 10 weeks...

..., monitored by in vivo microdialysis. Ovariectomized rats were tested under two conditions: (1) nonhormone-treated where Ang II infusion inhibits luteinizing hormone (LH) release, and (2) ovarian hormone-treated where Ang II stimulates LH secretion. Animals were ovariectomized and chronic guide cannulae were...

..., 20 and 21. This GnRH antagonist reduced plasma luteinizing hormone (LH) levels and increased pituitary LH content in both male and female 19-day-old fetuses from mothers adrenalectomized on day 14 of gestation. An inverse relationship between plasma testosterone and LH levels was noted in males...

... at birth induced 1 h later a slight but not significant increase in hypothalamic gonadotropin-releasing hormone (GnRH) and pituitary luteinizing hormone (LH) contents, reduced drastically plasma LH levels and completely prevented the postnatal surge of plasma testosterone which occurred normally...

.... Intact transgenic mice had significantly greater plasma luteinizing hormone (LH) levels than did normal littermate controls. Castration increased LH levels in normal mice but was without effect on plasma LH levels in the transgenic mice. In vitro LH secretion and pituitary LH content were higher...

...Carl W. Brango; Scott Whisnant; Robert L. Goodman These experiments tested the hypothesis that inhibitory catecholaminergic neural systems suppress tonic luteinizing hormone (LH) secretion in the prepubertal ewe lamb, as they do in the adult anestrous ewe. This was done by determining the effects...

... luteinizing hormone (LH) secretion, was studied electrophysiologically in 6 ovariectomized rhesus monkeys bearing bilateral arrays of recording elecrodes implanted in the mediobasal hypothalamus. ‘Volleys’ of increased multiunit activity (MUA) were recorded for 6–10 h in animals placed in primate chairs...

... (LH) release. In intact females under Saffan anaesthesia, bilateral stereotactic injections into the ZI of two GABA transaminase inhibitors [amino(oxy)acetic acid and γ-acetylene GABA] on the morning of pro-estrus or two GABA agonists on the afternoon of pro-estrus inhibited ovulation. The selective...

... and described the pattern of luteinizing hormone (LH) release during the postcastration rise in gonadotropin secretion 24 and 72 h after gonadectomy. In intact rats, the effect of hyperprolactinemia was determined by describing the pattern of LH secretion, pituitary GnRH receptor content and assessment...

... of Pediatrics and Genetics, University of Geneva School of Medicine, Geneva, Switzerland KeyWords. Melatonin GnRH LH FSH Puberty Rat Abstract. Melatonin administration has been shown to delay sexual maturation in male rats, through an action which involves decreased binding of gonadotropin-releasing...

... and noradrenaline (NA) nerve terminal systems. Serum thyroid-stimulating hormone (TSH), prolactin, luteinizing hormone (LH), follicle-stimulating hormone (FSH), vasopressin, corticosterone and testosterone levels were determined by radio-immunoassay procedures. Nicotine treatment and to a minor degree also acute...

...Alfredo O. Donoso Previous studies have suggested that gamma-aminobutyric acid (GABA) exerts inhibitory actions on luteinizing hormone (LH) secretion that are likely to be mediated by modifications in noradrenergic transmission. To explore further this hypothesis we have studied the effect...

...Robert L. Goodman Both dopaminergic (DA) and noradrenergic (NA) neural systems contribute to the suppression of luteinizing hormone (LH) pulse frequency in intact anestrous ewes. In this study, we explored the functional relationship between these two inhibitory neural systems by determining if DA...

...Akira Miyake; Shirou Ohtsuka; Takamichi Nishizaki; Keiichi Tasaka; Toshihiro Aono; Osamu Tanizawa; Atsushi Yamatodani; Takehiko Watanabe; Hiroshi Wada For determination of the roles of histamine and its receptors, H 1 and H 2 , in the control of basal and estrogen-induced LH-RH secretion...