Journal of Assisted Reproduction and Genetics, Vol. 12, No. 1, 1995 ANIMAL INVESTIGATIONS ANIMAL INVESTIGATIONS Recombinant-Human Luteinizing Hormone (r-hLH) as Ovulatory Stimulus in Superovulated Does* JOSI~ A. PEINADO, 1'4 IMMACULADA MOLINA, 2'5 MARCIAL PLA, 3 JESfJS A. F. TRESGUERRES, 1 and ALBERTO ROMEU 2 Submitted: December 15, 1994 Accepted: January 16, 1995 Purpose: To study the effects of r-hLH as ovulatory stim- ulus in does. Method: New Zealand does, 18 wk old, in estrus, received 25 IU of pregnant mare serum gonadotropin (PMSG) fol- lowed at 48 h either by 50 IU of r-hLH (n = 20) or hCG (n = 20) to induce follicular growth and ovulation. All does were previously artificially inseminated to avoid en- dogenous LH surge. Half of the animals receiving r-hLH (n = 10) or hCG (n = 10) were killed at 72 h after the hormone administration, and the remaining half were ldlled at 14 days. At 72 h the number of corpora lutea and preovulatory folliclds was determined, and fertilization rate, embryo quality, degree of embryonic development, and oviductal transit were all assessed. On Day 14 the number corpora lutea and implanted embryos were counted, and implantation rate was determined. Median and interquartile ranges were calculated for each param- eter. Results: At 72 h the median for corpora lutea was 8 (7-10) in the r-hLH group vs 13 (10-14) in the hCG group (P = 0.009); preopvulatory follicles were 7 (6-10) vs 0 (0-0) (P = 0.0007); the percentage of good-quality embryos was 71.4% (54.5-75) vs 33.3% (25-37.5) (P = 0.001), for in- * Presented at the 50th Annual Meeting of the American Fertility Society, San Antonio, Texas, November 5-10, 1994. 1Departamento de Fisiologfa, Facultad de Medicina, Univer- sidad Complutense de Madrid, 28040 Madrid, Spain. 2 Servicio de Reproducci6n, Hospital Universitario La Fe, Avenida de Campanar 21, 46009 Valencia, Spain. 3 Departamento de Ciencia Animal, Escuela T6cnica Superior de Ingenieros Agr6nomos, Universidad Polit6cnica de Valencia, 46022 Valencia, Spain. 4 Laboratorios Serono, S.A., 28006 Madrid, Spain. 5 To whom correspondence should be addressed. termediate-quality embryos it was 25% (14.3-36.4) vs 33.3% (25-38.5), and the percentage of degenerated em- bryos was 0% (0-12.5) vs 33.3% (25-37.5) (P = 0.015), respectively. Fertilization rates were similar in both groups. Embryonic development was more homogeneous in the animals receiving r-hLH (8 to >t16 cells) compared to those receiving hCG (2 to >i16 cells). The median of embryos still in oviducts at 72 h was significantly higher in the hCG group [6 (4-13)] than in the r-hLH group [0 (0-4)] (P = 0.41). At 14 days the median of corpora lutea was higher in the hCG [12 (11-16)] than in the r-hLH group [I0 (7-13)] (P = 0.008), but no differences were noted in the number of implanted embryos. Implantation rate was higher in the r-hLH group [100 (92.3-100)1 than in the hCG group [87.5 (83.3-94.1)] (P = 0.056). Conclusions- At the studied dose an ovulatory stimulus with r-hLH induced fewer follicles to ovulate than hCG. Recombinant-hLH produced superior embryo morpho- logical quality, a more homogeneous degree of embryo development, and more synchronous embryo transit than hCG. In spite of the larger number of ovulations follow- ing hCG, subsequent events essential for pregnancy were higher with r-hLH, offsetting differences in terms of im- planted embryos at 14 days of pregnancy. KEY WORDS: recombinant-human luteinizing hormone; ovula- tion induction; rabbits. INTRODUCTION It has been documented in the rabbit that hCG pro- duces a greater ovulation rate than the endogenous LH surge induced by mating. Human chorionic go- nadotropin also induced differences in terms of the initiation and duration of ovulation (1). This phe- 61 1058-0468/95/0100-0061507.50/0 9 1995 Plenum Publishing Corporation