Basal and LH-RH induced plasma FSH and LH levels were determined longitudinally in 41 patients aged 4 to 22 years with Turner's syndrome and in 4 male patients with prepubertal castration. In 12 patients with Turner's syndrome over 18 yrs of age without pubertal change, basal and LH-RH induced FSH levels studied at age 11--22 yrs were all significantly increased over normal levels. However, som...

BACKGROUND Theca cells play an important role in controlling ovarian steroidogenesis by providing aromatizable androgens for granulosa cell estrogen biosynthesis. Although it is well established that the steroidogenic activity of theca cells is mainly regulated by LH, the intracellular signal transduction mechanisms that regulate thecal proliferation and/or steroidogenesis remain obscure. In th...

Three species of luteinizing hormone (LH) designated as LH-A, -B, and -C, and containing 9, 8, and 4 NIH-LH-Sl units per mg were isolated from human pituitary glands by isoelectric focusing. The LH-A, -B, and -C each sedimented as a single boundary in the ultracentrifuge with ~20,~ of 2.34, 2.24, and 2.70 S, respectively. Amino acid analyses of LH-A, -B, and -C were very similar, although minor...

We compared five two-site immunometric assays (including three commercially available kits) for measuring lutropin (LH) in serum. Four of the assays involved monoclonal antibodies directed against the alpha-beta dimer, intact LH; these assays measured significantly lower concentrations of LH in 19 (out of 83) samples than did a commercial method not involving such antibodies. In five serum samp...

We assessed the time-dependent impact of estradiol on properties of the luteinizing hormone (LH) pulse signal in 12 hypoestrogenemic postmenopausal volunteers studied basally and after 1, 5, 10, and 30 d of estradiol delivery via an intravaginal Silastic ring. Computerized analysis of the plasma LH time series revealed a significant decrease in LH pulse frequency within 24 h of estrogen treatme...

Luteinizing hormone (LH) secretory profiles have been determined for the male bovine following castration and steroid replacement therapy. Serum LH concentrations increased approximately threefold during the first week following castration and thereafter remained elevated (6.6 +/- .7 ng/ml). Castrates not receiving steroid replacement showed a rhythmic pattern of LH release that was of high fre...

BACKGROUND In the learned helplessness (LH) paradigm, approximately 35% of rats are resilient to inescapable stress. METHODS The roles of brain-derived neurotrophic factor (BDNF) and dendritic spine density in the brain regions of LH (susceptible) and non-LH rats (resilient) were examined. Western blot analysis and Golgi staining were performed. RESULTS BDNF levels in the medial prefrontal ...

The effects of third ventricular injection of beta-endorphin (beta-EP) on spontaneous, brain stimulation-induced and estrogen-induced LH surges were studied in the adult female rat. It was found that beta-EP blocked the preovulatory surge of LH release and ovulation, while it did not affect LH release in response to LH-RH injection. The site of the beta-EP blockade of ovulation was proved to be...

Changes in the immunoreactivity of pituitary luteinizing hormone (LH) cells and in their fine structure were studied in 4-day-cyclic female rats along with the radioimmunoassay of pituitary and serum LH. Pituitary LH increased during diestrus (DE) and in early proestrus (PE) to a maximal level at noon of PE, followed by a marked decrease by 2100 h PE. Serum LH stayed at low levels in estrus (E)...

UNLABELLED Some adolescents with a history of idiopathic central precocious puberty (ICPP) develop hyperandrogenism. HYPOTHESIS Luteinizing hormone (LH) hypersecretion could be a common mechanism underlying ICPP and polycystic ovary syndrome. AIM To explore the GnRH-LH axis in those patients. DESIGN To compare overnight LH secretion in 7 healthy adolescents (CG) with that in patients with...