title: Effect of acute immunoneutralization of inhibin in ewes during the late luteal phase of the oestrous cycle on ovarian hormone secretion and follicular development during the subsequent follicular phase.
abstract: Ewes with ovarian autotransplants received either inhibin antiserum (10 ml i.v.; n = 6) or sheep serum (10 ml i.v.; n = 5) on day 10 of the luteal phase with additional daily injections (1 ml i.v.) from 48 h after the initial injection until the end of blood sampling, 9 days later. Luteal regression was induced by injection of prostaglandin F2 alpha (PGF2 alpha) 4.2 days after the initial plasma injection. Jugular and ovarian venous blood samples were taken every 4 h over the experimental period, and more frequent samples (every 10-15 min for 2-3 h) were taken to examine pulsatile secretory responses from the ovary to GnRH-induced (150 ng i.m. 1 and 4 days after initial treatment) or endogenous LH pulses (24 and 48 h after injection of PGF2 alpha). Plasma FSH concentrations, ovarian steroid secretion and ovarian follicular development were measured. Immunization against inhibin resulted in a two- to threefold increase (P < 0.001) in plasma FSH concentrations, which remained higher than controls until injection of PGF2 alpha. Within 24 h of immunization, there was an increase in the number of small ovarian follicles (P < 0.01) and by 4 days after treatment, immunized ewes had four or five (P < 0.01) large ovarian follicles and, despite little change in the basal steroid secretion, a four- to sixfold increase (P < 0.05) in the amplitude of the steroidogenic response to a GnRH-induced LH pulse.(ABSTRACT TRUNCATED AT 250 WORDS)
mesh_terms: D000735:Androstenedione / Q000378:metabolism; D000818:Animals; D015237:Dinoprost / Q000494:pharmacology; D004958:Estradiol / Q000378:metabolism; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood; D005498:Follicular Phase; D012739:Gonadal Steroid Hormones / Q000378:metabolism*; D007106:Immune Sera / Q000494:pharmacology; D007265:Inhibins / Q000276:immunology / Q000502:physiology*; D008183:Luteal Phase; D007986:Luteinizing Hormone / Q000097:blood; D006080:Ovarian Follicle / Q000502:physiology; D010053:Ovary / Q000378:metabolism* / Q000637:transplantation; D012756:Sheep / Q000502:physiology*
chemical_list: D012739:Gonadal Steroid Hormones; D007106:Immune Sera; D000735:Androstenedione; D004958:Estradiol; D007265:Inhibins; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone; D015237:Dinoprost