Follicular and luteal development in pregnant mares
Squires, E.L.; Ginther, O.J.
Journal of Reproduction and Fertility. Supplement 1975(23): 429-433
1975
ISSN/ISBN: 0449-3087 PMID: 1060820 Document Number: 95676
The ovaries of mares were examined at various stages of pregnancy and after hysterectomy. Progesterone concentration was determined in peripheral plasma of pregnant and hysterectomized mares and in uterine and ovarian venous plasma of pregnant mares. The primary corpus luteum of pregnancy remained functional until at least day 160 of gestation. Primary and secondary CL, and the placenta or uterus, all contribute to the total progesterone pool in mares during pregnancy. Similarities and differences in ovarian function observed between pregnant and hysterectomized mares suggested that PMSG does not seem to stimulate follicular development, but it prolongs the life-span and stimulates the secretory activity of the primary CL; it also induces ovulation and/or luteinization of secondary follicle in pregnant mares.