It has been previously shown that acute ethanol (EtOH) exposure in vivo resulted in suppression of serum LH and pituitary ßLH subunit mRNA levels in castrated male rats. While serum FSH levels also were noted to fall after in vivo, the mRNA for ßFSH was not altered. The aim of the present studies was to determine whether these effects could be accounted for by a direct EtOH effect at pituitary level. To this end we examined the direct effect of EtOH on LH and FSH synthesis and secretion utilizing dispersed anterior pituitary cells from gonadectomized adult male rats. After a 72 hour post dissociation healing period, the cells were exposed to media containing 0 or 200 mg% EtOH for one hour. The media was removed and the cells incubated with EtOH-free media for an additional 1, 3 or 6 hrs. In the EtOH exposed cells, secretion of both LH and FSH increased to > 300% (p < 0.001) of control. At 6 hrs after withdrawal of EtOH a significant reduction in both LH and FSH secretion was seen. Intracellular content of LH and FSH was unchanged before and after withdrawal of EtOH. Steady state levels of ßLH and ßFSH mRNA were unchanged at all time points. In a separate series of experiments, pituitary cells from gonadectomized adult male rats were continuously exposed to different concentrations of EtOH ranging from 0-400 mg% for 3 hrs. LH secretion was stimulated by 400 mgm% EtOH only, while the intracellular content of LH was significantly reduced with the 400 mg% dose. The secretion of FSH was stimulated by 200 mg% and 400 mg% high dose EtOH after 3 hours, with concomitant reduction in FSH pituitary content at both these EtOh dose levels. The mRNA for both ßLH and ßFSH was not different with any dose of EtOH compared to levels of control, non-EtOH exposed cells. We conclude that though there were similarities between in vivo and in vitro LH and FSH responses to EtOH, the differences reported here indicate that the in vivo responses are not totally explained by a direct EtOH effect at pituitary level. Rather, they must, in addition, reflect action at suprapituitary site(s), pituitary effects of EtOH metabolites or condensation products, and/or alterations in LH and FSH clearance.
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