title: A selective increase in circulating inhibin and inhibin pro-alphaC at the time of ovulation in the mare.
abstract: The relationship between a selective increase in circulating immunoreactive (ir)-inhibin and the time of ovulation was investigated in mares. Concentrations of plasma ir-inhibin were measured every 4 h during the periovulatory period. Inhibin pro-alphaC, a precursor protein of the inhibin alpha-subunit, was also measured. The changes in ir-inhibin and inhibin pro-alphaC in circulation were parallel. Concentrations of both ir-inhibin and inhibin pro-alphaC in the plasma increased at the same time when ovulatory follicles ruptured, and the peak levels of circulating ir-inhibin and inhibin pro-alphaC were maintained for 4-8 h. There was no selective increase in plasma concentrations of estradiol-17beta during the process of ovulation. These results suggest that the selective increase in ir-inhibin and inhibin pro-alphaC was caused by the absorption of follicular fluid after the rupture of ovulatory follicles. These results also suggest that the measuring of plasma concentrations of ir-inhibin or inhibin pro-alphaC in mares might be a useful method for detecting the time of ovulation.
authors.affiliation: Laboratory of Veterinary Physiology, Tokyo University of Agriculture and Technology, Tokyo 183-8509, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Nagaoka
authors.forename: Y
authors.initials: Y
authors.lastname: Nambo
authors.forename: N
authors.initials: N
authors.lastname: Nagamine
authors.forename: S I
authors.initials: SI
authors.lastname: Nagata
authors.forename: Y
authors.initials: Y
authors.lastname: Tanaka
authors.forename: H
authors.initials: H
authors.lastname: Shinbo
authors.forename: N
authors.initials: N
authors.lastname: Tsunoda
authors.forename: H
authors.initials: H
authors.lastname: Taniyama
authors.forename: G
authors.initials: G
authors.lastname: Watanabe
authors.forename: N P
authors.initials: NP
authors.lastname: Groome
authors.forename: K
authors.initials: K
authors.lastname: Taya
mesh_terms: D000818:Animals; D015415:Biomarkers; D001947:Breeding; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood; D006736:Horses / Q000502:physiology*; D007265:Inhibins / Q000032:analysis / Q000097:blood*; D007986:Luteinizing Hormone / Q000097:blood; D010060:Ovulation / Q000502:physiology*; D011374:Progesterone / Q000097:blood; D011498:Protein Precursors / Q000032:analysis / Q000097:blood*; D011863:Radioimmunoassay
chemical_list: D015415:Biomarkers; D011498:Protein Precursors; C095971:inhibin-alpha subunit precursor; D011374:Progesterone; D007265:Inhibins; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone