title: Effects of passive immunization against inhibin on ovulation rate and embryo recovery in holstein heifers.
abstract: The effects of acute neutralization of endogenous inhibin on ovulation rate and circulating FSH levels were investigated. Nine or ten days after estrus, 5 heifers were given a single injection of 75 ml iv inhibin antiserum produced in a castrated male goat, while another 5 were given the same amount of a castrated male goat serum. All heifers were given injections of PGF2alpha im at 48 h and 60 h after the serum injection. Those exhibiting an estrus were artificially inseminated with frozen-thawed semen. Seven or eight days after the insemination, ova or embryos were collected using a non-surgical method. Administration of inhibin antiserum resulted in a significant increase in the number of medium-sized follicles compared with the number in the control animals. The number of large follicles in the inhibin-neutralized animals was 4.8 +/- 2.4 (mean +/- SEM; n = 5) on the day of estrus, while there was a single large follicles in the ovaries of control animals. Seven or eight days after estrus, 3 to 16 ova or embryos were recovered from 4 of 5 animals, and 64 % of the total ova/embryos were transferable. Administration of inhibin antiserum produced a significant increase in the concentrations of plasma FSH from 12 to 72 h after the serum injection compared with the levels in the control animals (P < 0.05). After the onset of estrus, preovulatory LH and FSH surges were noted in inhibin-neutralized animals and magnitude of the rise in each hormone was similar to the control animals. The present study demonstrates that a single injection of the inhibin antiserum induces multiple ovulations probably by enhancing FSH secretion, and that recovery of embryos is equal to that observation after an ordinary FSH treatment.
authors.affiliation: Central Research Institute for F and L Zen-noh, Tsukuba, Ibaraki 300-33, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Takedomi
authors.forename: H
authors.initials: H
authors.lastname: Kaneko
authors.forename: Y
authors.initials: Y
authors.lastname: Aoyagi
authors.forename: M
authors.initials: M
authors.lastname: Konishi
authors.forename: H
authors.initials: H
authors.lastname: Kishi
authors.forename: G
authors.initials: G
authors.lastname: Watanabe
authors.forename: K
authors.initials: K
authors.lastname: Taya