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This is the first report of viable pregnancies established with ICSI after 24-hour incubation of washed ejaculated sperm from men with poor sperm parameters. Because both pregnancy rates and viable pregnancy rates were significantly increased compared with 2- to 4-hour-incubated historical controls, 24-hour incubation before ICSI may be beneficial in selecting the most favorable ejaculated sperm.

Pre-ovulatory peaks in oestradiol-17 beta concentrations were observed on days 1 or 2 and post-ovulatory peaks between days 4 and 7, both in jugular venous plasma and defatted milk, day 1 being the day of the onset of oestrus in the goats. Mean values of the magnitudes of these concentration peaks and of their timing (relative to oestrus) during the oestrus cycle did not differ significantly (P greater than 0.05) from those when the goats were mated and became pregnant. Pre-ovulatory oestradiol-17 beta peaks were invariably greater than the corresponding post-ovulatory peaks, as were peak concentrations in plasma relative to those in defatted milk collected on the same day. Mean intervals between the pre- and post-ovulatory peaks in oestradiol-17 beta concentrations were respectively 4.2 days for plasma and 4.0 days for defatted milk. Concentrations of oestradiol-17 beta in jugular venous plasma and defatted milk were strongly correlated: rank correlation coefficients for the three goats studied were 0.871, 0.668 and 0.739. It is suggested that in goats, as in cattle, ovarian follicular oestradiol-17 beta secretion approaching pre-ovulatory level is restored by 4 days after oestrus and its rapid decline after this time may be due to the inhibitory influence of the rapidly rising plasma progesterone concentration.

In the male rhesus monkey, the negative feedback regulation of gonadotropin secretion by the gonad involves a specific inhibitory action of a testicular hormone on FSH release at the level of the anterior pituitary gland. Neither circulating testosterone (T) nor estradiol appears to be able to account for the testicular inhibition of FSH in this species. The purpose of the present study was to begin to examine the role of gonadal peptides in this regard. To this end, an episodic pattern of activity in the pituitary-Leydig cell axis was restored in seven hypothalamus-lesioned male rhesus monkeys with a chronic and unchanging intermittent iv infusion of GnRH (0.1 microgram/min for 3 min every 3 h). This preparation, known as the hypophysiotropic clamp, has been described in detail previously. Charcoal-extracted porcine follicular fluid (pFF) was used as the source of gonadal peptides. In five animals, initiation of combined T replacement and pFF treatment (10-15 ml, sc, every 12 h for 8 days) maintained circulating FSH at concentrations similar to those observed before gonadectomy. Withdrawal of pFF treatment for 8 days while maintaining T replacement resulted in a progressive and dramatic rise in plasma FSH concentrations. Reinitiation of pFF treatment resulted in a return of circulating FSH concentrations toward precastration control values. Changes in LH secretion throughout the experiment were unremarkable. In an attempt to assess any nonspecific effects of porcine protein on gonadotropin secretion, the remaining two animals received charcoal-extracted pig serum instead of pFF. In these animals circulating FSH concentrations rose 7- to 8-fold during the 8 days of combined T replacement and pig serum treatment. These findings provide evidence to support the view that a testicular peptide, most probably inhibin, plays a major role in the negative feedback regulation of gonadotropin secretion in the monkey by exerting an inhibitory action on FSH secretion directly at the level of the anterior pituitary gland.

Circulating inhibin alpha concentrations were determined in infant, juvenile, and adult male rhesus monkeys with a RIA employing antisera to a synthetic fragment of the alpha-subunit of porcine inhibin. Binding of tracer, [DSer1,Nle5]human inhibin alpha(1-25)-Gly-125I-Tyr, to antibody was inhibited by standard, [DSer1,Nle5]human inhibin alpha(1-25)-Gly-Tyr. and by plasma from adult male monkeys in a parallel fashion. Castration in adults resulted in a 5-fold decline in the levels of immunoreactivity in plasma. Mean (+/- SE) plasma inhibin alpha concentrations in infants and adults (322.9 +/- 51.9 and 460.1 +/- 43.9 pg/ml, respectively) were significantly higher (P less than 0.05) than those in juveniles (191.3 +/- 28.3 pg/ml). Moreover, initiation of puberty in juvenile males, 13-18 months of age, with a chronic (10- to 12-week) intermittent iv infusion of GnRH (0.1 microgram/min for 3 min every 3 h) resulted in a progressive rise in circulating inhibin alpha that plateaued, after 5 weeks of pituitary stimulation, at concentrations (343.9 +/- 38.2 pg/ml) comparable to those of infants and adults and twice those observed before initiation of the pulsatile infusion of GnRH. Circulating FSH concentrations increased during the first week of GnRH stimulation from 2.7 +/- 0.1 ng/ml before treatment to 6.0 +/- 1.2 ng/ml, where they remained for the duration of the experiment. Testosterone secretion during the initiation of precocious puberty occurred in discrete episodes that were robustly correlated with GnRH-induced LH discharges. In contrast, changes in circulating inhibin alpha concentrations over the 3-h interval between GnRH pulses were unremarkable. Activation of Sertoli and Leydig cells during initiation of puberty in the juvenile males, as reflected by circulating inhibin alpha and testosterone concentrations, respectively, occurred with similar time courses. At the time of orchidectomy, 10-12 weeks after initiation of GnRH treatment, testicular tissue was prepared for histological examination. In spite of a 2-fold gain in testicular weight and in hypertrophy of Sertoli cells in association with GnRH stimulation, maturation of the germinal epithelium did not progress past prophase I spermatocytes, and the number of these latter cells was meager. These findings indicate that the testis of the infant primate, like that of the adult, secretes significant amounts of inhibin, and that the quiescent Sertoli cell of the juvenile males may be readily provoked by appropriate gonadotropin stimulation into producing inhibin. The results also fail to provide evidence for the view that changes in circulating inhibin concentrations are robustly related, in an inve