Lack of LH response to exogenous estradiol in heifers with ACTH-induced ovarian follicular cysts.
The aim of the present study was to examine the LH response to exogenous estradiol in 4 heifers with ACTH-induced ovarian follicular cysts. During the control experiment, administration of estradiol 24 hr after PGF2alpha in luteal phase heifers resulted in a LH response in all 4 heifers. The LH response was obtained between 16-20 hr after estradiol administration. The peak LH concentration (Mean +/- SEM; 5.1 +/- 0.8 ng/ml) during the control study was significantly different (P<0.05) from the concentration after cyst formation. None of the 4 heifers responded to estradiol after ovarian cyst formation. This result suggests that heifers with ACTH-induced ovarian follicular cysts may have a defective hypothalamio-pituitary response to exogenous estradiol similar to cows with spontaneous ovarian cysts.
Ribadu
A Y
AY
Department of Veterinary Obstetrics & Gynecology, Rakuno Gakuen University, Ebetsu, Hokkaido, Japan.
Nakada
K
K
Tanaka
Y
Y
Moriyoshi
M
M
Zhang
W C
WC
Nakao
T
T
D000324:Adrenocorticotropic Hormone; D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000097:blood*; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D007986:Luteinizing Hormone / Q000097:blood*; D010048:Ovarian Cysts / Q000097:blood / Q000139:chemically induced / Q000662:veterinary*
D004958:Estradiol; D000324:Adrenocorticotropic Hormone; D007986:Luteinizing Hormone