Plasma concentrations of immunoreactive inhibin and gonadotropins following removal of ovarian follicles in the domestic hen.
In the domestic hen, the preovulatory follicles are arranged in a hierarchy. The largest (F1) follicle ovulates first, the second largest (F2) follicle ovulates approximately 26 h later, and so on. The nature of this regulation is not known. Inhibin has been implicated in the feedback regulation of FSH in mammals, and bioactive as well as immunoreactive inhibin has been demonstrated in chickens. The present experiments were conducted with two aims: 1) to determine the plasma level of immunoreactive inhibin in response to removal of various numbers of preovulatory follicles and 2) to assess the gonadotropin response to such follicle removal. In experiment 1, the F1 (n = 4), F1 + F2 (n = 5), F1 + F2 + F3 (n = 5), and F1 + F2 + F3 + F4 (n = 4) follicles were removed surgically. Sham-operated animals served as controls. Blood samples were taken at time 0 (prior to surgery) and at 6, 24, and 48 h after surgery. In experiment 2, animals were sham-operated (n = 5) or the F1-F4 (n = 4) or F1-F4 plus small yellow follicles (SYF; n = 5) were removed. Blood samples were removed at time 0 and at 3, 6, and 24 h and at daily intervals until Day 10 after surgery. In both experiments, plasma immunoreactive inhibin was significantly lowered (p < 0.001) and plasma FSH was acutely increased (p < 0.05) by follicle removal. Plasma LH was decreased at some time points after follicle removal.(ABSTRACT TRUNCATED AT 250 WORDS)
Johnson
P A
PA
Department of Animal Science, Cornell University, Ithaca, New York 14853.
Brooks
C
C
Wang
S Y
SY
Chen
C C
CC
D000818:Animals; D002645:Chickens; D005246:Feedback; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood*; D007265:Inhibins / Q000097:blood*; D007986:Luteinizing Hormone / Q000097:blood*; D006080:Ovarian Follicle / Q000502:physiology* / Q000601:surgery; D010052:Ovariectomy; D013997:Time Factors
D007265:Inhibins; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone