FURTHER CHARACTERIZATION OF THE IMPACT OF ETHANOL ON BETA-LH - ALTERATIONS IN POLYRIBOSOME ASSOCIATION OF BETA-LH MESSENGER-RNA

We have previously reported a decrease in Luteinizing Hormone (LH) lev els in serum after in vivo acute ethanol exposure in male rats. Accomp anying these changes, a rapid and marked decrease of beta-LH mRNA was observed. A similar decrease was not detected in the common alpha-subu nit or beta-FSH mRNA. The studies presented here examined the possible mechanisms of decreasing beta-LH mRNA by using S1 nuclease protection assay to evaluate the effect of acute ethanol exposure on the levels of beta-LH heteronuclear RNA (hnRNA). There was no significant differe nce detected in the level of beta-LH hnRNA after ethanol exposure. Pol ysome distribution analysis was used to evaluate the association and d isassociation of beta-LH mRNA with polyribosomes since non-polyribosom e associated mRNA may be more vulnerable to degradation by RNAases. Th e results indicated a decrease in the association of the beta-LH mRNA with polysomes following acute ethanol exposure. This decrease in poly ribosome association would increase the exposure of the beta-LH transc ript making it more susceptible to RNases. We conclude that the decrea se in steady-state beta-LH mRNA levels after ethanol exposure occurs b ecause of increasing degradation of the transcript rendered vulnerable by displacement from polysomes and not through a decreased transcript ional rate.