The effect of "binge" ethanol exposure on growth hormone and prolactin gene expression and secretion

The effects of ethanol (EtOH) on GH and PRL have been previously explored, and a dicotomy in results noted. While serum GH levels appear to fall after EtOH exposure, PRL levels rise. We have attempted to expand these studies by examining the impact of acute or "binge" EtOH in vivo on GH and PRL synthesis and secretion. At 0.5, 1.5, and 3.0 h after one dose of ip EtOH, serum GH levels fell significantly compared with those seen in saline-injected controls. This correlated with a fall in GH mRNA levels, but no change in pituitary GH content. Conversely, serum PRL levels rose significantly, while the mRNA for PRL decreased by approximately 20%. There was no change in pituitary PRL content. Interestingly, the mRNA for pit-1 (GHF-1), a transcription factor important to both GH and PRL gene expression, was unchanged at any time point. Despite the fall in GH and PRL mRNA levels, the pituitary cAMP content was markedly elevated at 0.5 h, with no change at any other time point. In summary, acute EtOH exposure in vivo appears to dampen both GH and PRL synthesis, while serum levels behave dissimilarily. Possible explanations for these findings are discussed.