The effects of oxytocin on dispersed luteal cells from human corpora lutea of the menstrual cycle were studied. Oxytocin at a concentration of 4 mi.u./ml produced a slight increase in basal progesterone production. However, higher oxytocin concentrations (400 and 800 mi.u./ml) markedly inhibited both basal and human chorionic gonadotrophin-induced progesterone production. These data provide evidence for an effect of oxytocin on the human corpus luteum. In view of the inhibitory action of oxytocin, increased secretion of this hormone may be important in the demise of the corpus luteum at the end of the menstrual cycle.

No abstract

With the needs of experienced teachers potentially overshadowed by a focus on recruitment, the purpose of this study was to retrospectively explore the reasons why three experienced physical education teachers resigned. They were interviewed through Louis and Smith's (1990) quality of work life (QWL) model. Data suggested shared dissatisfactions related to the lack of "genuine" opportunities to participate in educational debate and decision making, and limited professional respect shown by administrators and parents. A physical education teacher's "use-by date" was proposed. Unless these issues are further explored and addressed, quality teachers will continue to abandon the service.

The effects of prolactin on steroidogenesis were studied in dispersed luteal cells prepared from human corpora lutea of the menstrual cycle. Prolactin, at concentrations of 0.1-1000 ng/ml, had no effect on progesterone production by luteal cells during short-term incubation (3 h). However, in two out of five corpora lutea, higher concentrations of prolactin (100 and 1000 ng/ml) significantly reduced the oestradiol-17 beta production induced by human chorionic gonadotrophin (hCG; 10 i.u./ml); lower doses of prolactin had little effect. In the remaining corpora lutea, prolactin failed to affect either basal or hCG-induced production of oestradiol-17 beta. These results are discussed in relation to the mechanism by which prolactin influences human ovarian function.

In acute incubation (3 h) LH-RH, at concentrations of 101\p=n-\106 pg/ml, failed to affect either basal or hCG-induced progesterone production by human luteal cells, from tissue taken in the early, mid or late luteal phase.