title: Changes in serum concentrations of immunoreactive inhibin during the oestrous cycle of the rat.
abstract: Serum and ovarian concentrations of inhibin during the oestrous cycle of rats were determined by a radioimmunoassay (RIA) based on a porcine inhibin RIA. Serum concentrations of LH, FSH, oestradiol-17 beta, progesterone and testosterone were also determined during the cycle. Serum concentrations of inhibin were high (8.47 +/- 0.58 micrograms/l) during the morning of pro-oestrus and then dropped sharply to the lowest level (3.21 +/- 0.38 micrograms/l) at 24.00 h on the day of pro-oestrus after the preovulatory LH and FSH surge. Inhibin concentrations then recovered rapidly, with a peak (7.94 +/- 0.97 micrograms/l) at 15.00 h on the day of oestrus. Inhibin concentrations in serum dropped again to their second lowest value (4.00 +/- 0.12 micrograms/l) at 24.00 h on the day of oestrus. The largest FSH surge observed from midnight of pro-oestrus to the morning of oestrus (the so-called second FSH surge) was shown to be inversely related to the changes in serum concentrations of inhibin, suggesting a close relationship between the serum FSH and inhibin concentrations in cyclic rats.
authors.affiliation: Department of Obstetrics and Gynecology, Gunma University School of Medicine, Maebashi, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Hasegawa
authors.forename: K
authors.initials: K
authors.lastname: Miyamoto
authors.forename: M
authors.initials: M
authors.lastname: Igarashi
mesh_terms: D000818:Animals; D001681:Biological Assay; D004971:Estrus / Q000097:blood*; D005260:Female; D012739:Gonadal Steroid Hormones / Q000097:blood; D007265:Inhibins / Q000097:blood* / Q000378:metabolism; D010053:Ovary / Q000378:metabolism; D010902:Pituitary Gland / Q000378:metabolism; D010907:Pituitary Hormones / Q000378:metabolism; D011863:Radioimmunoassay / Q000379:methods; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D012739:Gonadal Steroid Hormones; D010907:Pituitary Hormones; D007265:Inhibins