The present study was designed to investigate a possible role of endogenous nitric oxide (NO) in the adrenal response to an acute alcohol administration in female rats. To this end, Nω-nitro-l-arginine-methyl ester (l-NAME), a competitive inhibitor of all isoforms of NO synthase, was used.
Adult female Wistar rats showing diestrus Day 1 were treated with: (a) ethanol (2 or 4 g/kg, intraperitoneally); (b) l-NAME (30 or 50 mg/kg, subcutaneously) followed by either ethanol or saline 3 h later. Untreated and saline-injected rats were used as controls. The animals were killed 30 min after last injection. Adrenal cortex was analyzed morphometrically, and plasma levels of adrenocorticotropic hormone (ACTH) and serum concentrations of corticosterone were determined.
Acute ethanol treatment enhanced the levels of ACTH and corticosterone in a dose-dependent manner. Stereological analysis revealed that acute alcohol administration induced a significant increase in absolute volume of the cortex and the zona fasciculata (ZF). In addition, ethanol at a dose of 4 g/kg increased volume density and length of the capillaries in the ZF. However, other stereological parameters were unaffected by alcohol exposure. Pretreatment with both doses of l-NAME had no effect on ethanol-induced changes.
Obtained findings indicate that acute ethanol treatment stimulates the activity of the adrenal cortex and that this effect is not mediated by endogenous NO in female rats under these experimental conditions.
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