Suppression of follicular development after chronic LHRH immunoneutralization in the ewe.
Active immunization of 6 Damline ewes against LHRH during seasonal anoestrus resulted in an inhibition of ovarian cyclicity throughout 2 subsequent breeding seasons. This was associated with a significant suppression of plasma LH and FSH concentrations but no significant effect on prolactin. The ovaries of LHRH-immunized ewes 30 months after primary immunization contained no follicles greater than 2.5 mm in diameter and a greater proportion of follicles between 1 and 2 mm were atretic than in control ewes (N = 8). In-vitro production of testosterone and androstenedione were similar in follicles 1-2 mm in both control and LHRH-immunized ewes (N = 6) and all had little or no ability to secrete oestradiol. However, basal and hCG-stimulated progesterone secretion was suppressed in the follicles from LHRH-immunized ewes. These results show that follicular development beyond 2.5 mm in the ewe is dependent on adequate stimulation by both LH and FSH.
McNeilly
A S
AS
Jonassen
J A
JA
Fraser
H M
HM
D000780:Anestrus; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood; D005496:Follicular Atresia; D007987:Gonadotropin-Releasing Hormone / Q000276:immunology* / Q000502:physiology*; D007110:Immunity, Active; D007986:Luteinizing Hormone / Q000097:blood; D006080:Ovarian Follicle / Q000378:metabolism / Q000502:physiology*; D010060:Ovulation; D011374:Progesterone / Q000378:metabolism; D011388:Prolactin / Q000097:blood; D012756:Sheep
D000911:Antibodies, Monoclonal; D007987:Gonadotropin-Releasing Hormone; D011374:Progesterone; D011388:Prolactin; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone