Acute ethanol treatment increases level of progesterone in ovariectomized rats.

To determine whether an increased level of progesterone in adult female rats after acute ethanol treatment, described previously in our study, is the result of activation of adrenal glands, we analyzed adrenal cortex morphologically and measured serum levels of corticosterone and progesterone in ovariectomized rats. In addition, a possible involvement of the opioid system in an observed phenomenon was tested. Adult female Wistar rats were ovariectomized, and 3 weeks after surgery they were treated intraperitoneally with (a) ethanol (4 g/kg), (b) naltrexone (5 mg/kg), followed by ethanol (4 g/kg) 45 min later, and (c) naltrexone (5 mg/kg), followed by saline 45 min later. Untreated and saline-injected rats were used as controls. The animals were killed 0.5 h after ethanol administration. Morphometric analysis was carried out on paraffin sections of adrenal glands, stained with hematoxylin-eosin, and the following parameters were determined: absolute volume of the zona glomerulosa, the zona fasciculata, and the zona reticularis; numerical density, volume, and the mean diameter of adrenocortical cells and of their nuclei; and mean diameter and length of capillaries. The results showed that acute ethanol treatment significantly increased absolute volume of the zona fasciculata and length of its capillaries but did not alter other stereological parameters. Also, serum levels of corticosterone and progesterone were enhanced. Pretreatment with naltrexone had no effect on ethanol-induced changes. These findings are consistent with our previous hypothesis that an ethanol-induced increase of the progesterone level in adult female rats originates from the adrenal cortex.