OVARIAN RESPONSE AND CLEAVAGE RATE OF OVA IN CONTROL AND FSH-PRIMED RABBITS RECEIVING VARYING LEVELS OF LUTEINIZING HORMONE

Abstract
The superovulatory response of Dutch-belted does receiving 0.10, 0.25, 0.50, 1.00, 2.00 and 4.00 mg of LH/kg of body weight following priming with twice daily injections of 0.50 mg of FSH each for 3 days was examined. The does were inseminated immediately following LH injection. Rabbits given the lowest level of LH did not ovulate, and an average of 1.0 ovulation points was obtained following the 0.25 mg level of LH. All does receiving [greater than or equal to] 0.50 mg of LH ovulated, with an average of 33.7, 40.0, 45.1 and 35.6 ovulation points for the 0.50, 1.00, 2.00 and 4.00 mg levels, respectively (P> 0.10). Some large unruptured follicles remained in all groups after they received LH. The proportion of cleaved ova collected from FSH [follicle-stimulating hormone]-primed does 26, 28 and 30 hr. after LH administration was 68, 86 and 91% respectively, whereas in non-primed controls all fertilized ova appeared to have cleaved by 26 hr. This difference is attributed to the longer time required for ovulation to be completed in FSH-primed animals rather than in delay in cleavage rate following fertilization.