SUPEROVULATION AND EMBRYO CULTURE IN-VITRO FOLLOWING TREATMENT WITH ULTRA-PURE FOLLICLE-STIMULATING-HORMONE IN CATS

Oestrus was induced in nine prepubertal and nine adult cats using thre e different doses (2.5, 10 and 30 iu divided into five daily doses) of an ultra-pure preparation of porcine follicle-stimulating hormone (FS H) without any luteinizing hormone activity. After 5 days of treatment , ovulation was induced by two daily injections of human chorionic gon adotrophin and the cats were mated. One week later (on day 12) the ova ries were examined for the number of unovulated follicles and ovulatio n sites. In eight of the nine prepubertal cats the ovaries had 20-90 l arge follicles per cat and only two cats ovulated (8-9 corpora lutea). All adults responded and ovulated. Adult cats had 3-40 large follicle s and 6-35 corpora lutea each. In each group, ovarian response (and ov ulation rate) was related to the dose of FSH. The 79 embryos that coul d be recovered at days 11-13 after the onset of treatment, using a new technique, were assessed; those of good quality were cultured until c omplete degeneration. One eight-cell embryo was cultured for 12 days t hrough the blastocyst to the gastrula-somite stage. With the highest F SH dosage there was increased degeneration of embryos. This may be ass ociated with the high oestrogen concentrations that were produced duri ng oestrus induction. Potential culture of feline embryos up to the ad vanced blastocyst stage in modified phosphate-buffered saline suppleme nted with fetal calf serum was demonstrated.