[Effects of dehydroepiandrosterone on blood cells of the rat]. / Effectos de la dehidroepiandrosterona sobre las células sanguíneas de la rata.

The effects of dehydroepiandrosterone (DHEA) on haemoglobin, hematocrit and white cell counts values were studied in male and female rats, castrated rats and pregnant rats. After 5 continuous days of DHEA administrated subcutaneously (80 mg/kg/d; body w.) haemoglobin and hematocrit values were similar those values obtained before the treatment. White cell counts were reduced (40%) in female no castrated rats due to a significantly lymphopenia. The white cell counts were increased in castrated rats and with DHEA administration there were reduced to the initial values. Estradiol treatment had the same effect as DHEA on castrated rats. These data suggest that DHEA administrated to castrated or sexually active male and female rats affects the white cells without important effects on red blood cells.

Inhibition of in vitro human chorionic gonadotropin-stimulated testosterone production in testis and of ovulation in the rat by charcoal-treated rat testicular extract.

Previously, we described the presence of a factor obtained from a 105,000 X g supernatant of rat testis that was found to inhibit human chorionic gonadotropin (hCG) binding to gonadal receptors. In the present study, similarly prepared testicular extract was tested for its effects on in vitro hCG-stimulated testosterone production by isolated testis interstitial cells and for its effect on spontaneous ovulation in the rat. Incubation of interstitial cells with charcoal-treated extract significantly inhibited the steroidogenic response to hCG in a dose-related manner. This inhibition was also apparent after heating the extract for 10 min at 100 degrees C. Preincubation of the cells with charcoal-treated extract resulted in an inhibitory effect that was not readily reversed by subsequent addition of hCG, revealing an element of irreversibility in the mechanism of inhibition. A single i.p. injection of testicular extract given between 1430-1630 h of proestrus inhibited spontaneous ovulation in the rat. This effect was also observed after heating the extract for 10 min at 100 degrees C; in contrast, no significant effect was obtained with the injection of a similar dose of liver extract. Administration of 5 IU hCG after pretreatment with the testicular extract did not reverse the inhibitory effect on ovulation, indicating that this effect was probably not exerted at the hypothalamus-pituitary level. It is concluded that the aqueous testicular extract contains a factor able to antagonize the physiological events mediated by luteinizing hormone (LH)/hCG, and that this factor is consistent with the presence of an LH/hCG-binding inhibitory activity in rat testis.