Tofupill lacks peripheral estrogen-like actions in the rat reproductive tract.

OBJECTIVE: The objective of this study was to evaluate the estrogenic effect of phytoestrogens contained in a commercial food supplement (Tofupill) on the reproductive tract of ovariectomized rats. METHODS: Food supplement (3.4 or 10.2 mg/kg) and conjugated equine estrogens (CEE, 31 or 100 microg/kg) were orally administered, daily during 14 days to ovariectomized rats. At the end of treatment, the following determinations were done: dry and wet uterine weight, vaginal epithelium condition, and uterine serotonin-induced contractile response. A group treated with 17beta-estradiol was included as control for serotonin-induced contractile response. RESULTS: Food supplement did not display clear estrogenic effects on vaginal epithelium, uterine weight or myometrial sensitivity to serotonin, whereas high doses of conjugated equine estrogens showed estrogenic action. CONCLUSIONS: The present data showed that Tofupill displayed a lower estrogenic effect than conjugated equine estrogens, which are one of the most commonly used hormone replacement therapy for postmenopausal women. However, further studies are needed to evaluate the risk associated to the use of Tofupill as an alternative to hormone replacement therapy for postmenopausal women.

Anatomical differences in uterine sensitivity to prostaglandin F(2alpha) and serotonin in non-pregnant rats.

The ovarian steroids regulate the sensitivity of a population of uterine receptors to prostaglandin F(2alpha), serotonin and oxytocin. However, the uterine sensitivity to prostaglandin F(2alpha) and oxytocin does not coincide with the estrogen-induced increase in the number of receptors. Anatomical differences affect the uterine sensitivity to agonists. We investigated whether anatomical differences between ovarian and cervical uterine regions modulate the hormone-regulated sensitivity to prostaglandin F(2alpha), serotonin and oxytocin. Non-cumulative concentration-response curves for these agonists were recorded for ovarian and cervical uterine segments from adult ovariectomized rats treated with 17beta-estradiol, 17beta-estradiol+progesterone, or vehicle. The ovarian segments displayed a higher maximal response (E(max)) to prostaglandin F(2alpha) and a lower E(max) to serotonin than the cervical segments. Both uterine segments displayed a similar sensitivity to oxytocin. The ovariectomized controls displayed the highest E(max) and the lowest effective concentration 50 (EC(50)) for oxytocin and prostaglandin F(2alpha). Anatomical differences between ovarian and cervical uterine regions modulate the hormonal regulation of uterine sensitivity to serotonin and prostaglandin F(2alpha) in the non-pregnant rat uterus.

Effects of intrathecal administration of adrenergic agonists on the frequency of copulatory pelvic thrusting of the male rat

The effects of the intrathecal perispinal administration of adregergic agonists on the characteristic of frequency, duration, and vigor of pelvic thrusting displayed by male rats during copulation was assessed by an accelerometric technique. A different dose of one drug (noradrenaline, clonidine or isoproterenol) and saline as control was administered at the lumbosacral level of the spinal cord to sexually active male rats in tests of sexual behavior performed at weekly intervals. The intrathecal administration of noradrenaline (alpha-adrenoceptor agonist) increased the frequency of pelvic thrusting in mount and intromission responses, whereas both the alpha2-adrenoceptor agonist clinidine (25 µg) and the ß-adrenoceptor agonist isoproterenol ( 40 µg) reduced the frequency of pelvic thrusting in these responses as compared to values obtained under the intrathecal administration of saline. On the other hand, the duration of the thrusting trains and the potency or vigor of pelvic thrusting in mounts and intromissions did not differ from values obtained under saline treatment. These findings indicate a possible participation of noradrenaline in the modulation of the spinal mechanisms involved in the generation of rhytmic pelvic thrustint performed by the male rat during copulation