Ovarian changes during early pregnancy in pony mares in relation to PMSG production.
The ovaries of twenty pregnant mares were examined daily, per rectum, for the first 4 months of gestation and note was made of their estimated size and follicular content. Serial blood samples from sixteen of the mares were assayed for PMSG. A marked seasonal effect was noted on ovarian size, follicular content and ovulation rate during pregnancy but there was no such effect on PMSG production. It is concluded that PMSG is synergistic with gonadotrophins of pituitary origin and that the latter hormone are the primary stimulus on the ovary of the pregnant horse.
D000818:Animals; D005260:Female; D006064:Gonadotropins, Equine / Q000096:biosynthesis* / Q000097:blood; D006736:Horses / Q000502:physiology*; D006080:Ovarian Follicle / Q000033:anatomy & histology; D010053:Ovary / Q000502:physiology*; D010060:Ovulation; D011247:Pregnancy; D011270:Pregnancy, Animal; D012621:Seasons; D013997:Time Factors
D006064:Gonadotropins, Equine