Egg laying begins in domestic hens, reared on short daylengths, at about day 147 of age and is advanced by photostimulation after but not before about day 42 of age. The development of this response at day 42 may be facilitated by oestrogen. This hypothesis was investigated in prepubertal hens, reared on short daylengths, by comparing the effects of oestrogen treatment on pituitary and plasma F...

The effect of follicle stimulating hormone (FSH) treatment on the pituitary response to gonadotrophin-releasing hormone (GnRH) was studied in rats in various reproductive conditions. A 3-day treatment of cycling rats with FSH (Metrodin; 10 IU/injection) lowered the spontaneous pre-ovulatory. LH-surge and suppressed the pituitary luteinizing hormone (LH) response to GnRH. FSH also suppressed the...

OBJECTIVE To evaluate the relationship between serum gonadotropin level and parameters related to insulin resistance in Korean women with polycystic ovary syndrome (PCOS). METHODS This retrospective study included 138 women aged 18 to 35 years who were newly diagnosed with PCOS according to the Rotterdam consensus. Participants were divided into three groups based on the serum luteinizing hor...

The development of a specific, sensitive homologous ovine follicle stimulating hormone (FSH) radioimmunoassay (RIA) is described. The key procedural modifications of basic RIA methods were immunoabsorpt ion of the anti-ovine FSH serum with lutenizing hormone (LH) to improve specificity and adsorption chromatography of the radioiodinated ovine FSH on hydroxyapat i te (HTP) to improve immunoreact...

Serum FSH and LH levels were estimated by radioimmunoassay following single subcutaneous administration, and repeated subcutaneous administration at various intervals in immature male rats. Single injection of LH-RH induced slight increase in FSH levels in comparison with considerable increase in LH. By two successive injections, the release of FSH was markedly stimulated when the time interval...

As is the case in other tetrapod species, the chicken gonadotropins LH and FSH consist of a common alpha subunit and a hormone-specific beta subunit. Gonadotrophs containing LH were shown earlier to be distributed throughout both the caudal and cephalic lobes of the chicken anterior pituitary, but the cellular distribution of FSH in avian species is still uncertain. The purpose of this study wa...

The relative r\l=o^\lesof FSH and LH in ovulation induction in immature and adult cycling rats and hamsters have been evaluated. Both heterologous purified pituitary hormones and homologous crude pituitary extracts have been used as ovulatory stimuli in immature animals primed with PMSG. Well-characterized FSH and LH antisera have been used in the above model systems to achieve specific neutral...

Increasing interest in events regulating gonadotropin synthesis and secretion led to the reexamination, by radioimmunoassay (RIA), of the pituitary content of luteinizing hormone (LH) and follicle stimulating hormone (FSH). In a preliminary experiment, the importance of the composition of the solvent used to homogenize pituitaries on the detection of LH and FSH was demonstrated by RIA. Experime...