Sperm Release From the Oviductal Epithelium Depends on Ca(2+) Influx Upon Activation of CB1 and TRPV1 by Anandamide.

The oviduct acts as a functional sperm reservoir in many mammalian species. Both binding and release of spermatozoa from the oviductal epithelium are mainly modulated by sperm capacitation. Several molecules from oviductal fluid are involved in the regulation of sperm function. Anandamide is a lipid mediator involved in reproductive physiology. Previously, we demonstrated that anandamide, through activation of the cannabinoid receptor type 1 (CB1), promotes sperm release from bovine oviductal epithelial cells, and through CB1 and the transient receptor potential vanilloid 1 (TRPV1), induces sperm capacitation. Herein we investigate co-activation between CB1 and TRPV1, and Ca(2+) influx as part of the mechanism of action of anandamide during sperm release from oviductal cells. Our results indicate that in the absence of Ca(2+) anandamide failed to release spermatozoa from oviductal epithelial cells. Additionally, sperm release promoted by cannabinoid and vanilloid agonists was abolished when the spermatozoa were preloaded with BAPTA-AM, a Ca(2+) chelator. We also determined Ca(2+) levels in spermatozoa preloaded with FURA2-AM co-cultured with oviductal cells and incubated with different cannabinoid and vanilloid agonists. The incubation with different agonists induced Ca(2+) influx, which was abolished by CB1 or TRPV1 antagonists. Our results also suggest that a phospholypase C (PLC) might mediate the activation of CB1 and TRPV1 in sperm release from the bovine oviduct. Therefore, our findings indicate that anandamide, through CB1 and TRPV1 activation, is involved in sperm release from the oviductal reservoir. An increase of sperm Ca(2+) levels and the PLC activation might be involved in anandamide signaling pathway.

Postcoital treatment with levonorgestrel does not disrupt postfertilization events in the rat.

Levonorgestrel (LNG), a progestin widely used for regular hormonal contraception, is also used for emergency contraception (EC) to prevent pregnancy after unprotected intercourse. However, its mode of action in EC is only partially understood. One unresolved question is whether or not EC prevents pregnancy by interfering with postfertilization events. Here, we report the effects of acute treatment with LNG upon ovulation, fertilization and implantation in the rat. LNG inhibited ovulation totally or partially, depending on the timing of treatment and/or total dose administered, whereas it had no effect on fertilization or implantation when it was administered shortly before or after mating, or before implantation. It is concluded that acute postcoital administration of LNG at doses several-fold higher than those used for EC in women, which are able to inhibit ovulation, had no postfertilization effect that impairs fertility in the rat.

Validation of the dual analyte assay of the oestrone:pregnanediol ratio in monitoring ovarian function.

The purpose of this study was to validate the dual analyte system (Boots Celltech Ltd, Slough, UK) as a marker of ovarian function. For this purpose the urinary profile of the ratio of oestrone-3-glucuronide to pregnanediol-3-glucuronide in urine (E13G/PD3G) was compared with plasma concentrations of oestradiol, progesterone, luteinizing hormone (LH) and follicle stimulating hormone from day 8-24 of the menstrual cycle in 23 women. Daily transvaginal ultrasound was also performed from day 8 of the cycle until sonographic evidence of follicular rupture. The ratio of urinary metabolites exhibited a maximum value close to ovulation. In the majority of cases this coincided with the day of LH peak, and was followed by follicular rupture within the next 24 h in 74% of cases. The assay gives a good marker of ovulation, however, it is unlikely to help in detecting the initiation of the fertile period or the quality of the menstrual cycle.

Embryos of different ages transferred to the rat oviduct enter the uterus at different times.

Indirect evidence of embryo signalling to the oviduct was sought in rats by examining the transport of embryos of different ages. One-cell or four-cell embryos were transferred to the oviducts of recipient rats on Day 1 of pregnancy, and the number, condition, and location of native and transferred embryos was assessed on Day 4. To control for the effect of the presence of foreign embryos and excess number of eggs and the transfer procedure upon the fate of native embryos, other groups of rats were sham-operated or left undisturbed. Recipients had a mean number of ova significantly higher than controls. In controls and recipients of 1-cell embryos, the majority of eggs reached the morula stage and all of them were located in the oviducts. In those animals receiving 4-cell embryos, half of the eggs had reached the blastocyst stage and 28% were in the uteri (p less than 0.005). These results support the idea that advanced embryos can influence the timing of their entrance to the uterus in rats.

Luteinizing hormone content of the pituitary gland in pregnant and non-pregnant women.

PIP: Pituitary glands were obtained from autopsies of women who had died suddenly during normal pregnancy (8), a few days after a septic abortion (17), or from traumatic injuries while nonpregnant (19). The adenohypophyseal content of immunoreactive luteinizing hormone (LH) was measured by means of solid phase radioimmunoassay. The LH content was significantly (p .0001) lower in pregnant women than in nonpregnant women; the same was true (p .0005) for post-abortion women versus nonpregnant women. The level of LH declined progressively with age of gestation in pregnant women; the correlation was .99.^ieng