Relationship between the fall in growth hormone secretion at birth and the onset of nonshivering thermogenesis is independent of beta adrenergic stimulation

Effect of STAT5b on rat liver alcohol dehydrogenase

Growth hormone (GH) enhances rat liver alcohol dehydrogenase (ADH) due to an increase in enzyme synthesis, which is mediated at the level of transcription. Previous studies have shown that the effect of GH in enhancing activation of the ADH promoter is mediated by C/EBP beta binding to region -22 to -11 relative to the start of transcription. In this study, STAT5b and C/EBP beta were found to bind to adjacent nucleotide sequences on a region between -226 and -194. Expression vectors for both STAT5b and C/EBP beta independently activated the promoter. Furthermore, the expression vector for the GH receptor also activated the ADH promoter, and this effect was abrogated by mutations of the adjacent STAT5b and C/EBP beta binding sites. These observations indicate that the enhancing effect of GH is mediated by both STAT5b and C/EBP beta.