Enhancement of ovulation by luteinizing hormone in cyclic albino rats

Treatment of cyclic albino rats with equine luteinizing hormone (LH) on the afternoon of proestrus significantly enhanced ovulatory capacity. The number of ova shed and the healthy corpora lutea in the ovaries were significantly increased. Ovarian proteolytic enzymes also increased significantly with LH treatment. The histologically normal graafian follicles bound to become atretic in the vehicle-treated animals were altogether absent in the LH-treated rats on the day of estrus. These results indicate that LH enhances the number of ovulations by reducing the preovulatory follicles from atresia and facilitates their rupture by increasing the amount of proteolytic enzymes in them. A single injection of porcine follicle stimulating hormone (FSH), human chorionic gonadotrophin (hCG), and pregnant mare's serum gonadotrophin (PMSG) given separately was ineffective in inducing superovulation in cyclic albino rats.