Hyperprolactinemia following chronic alcohol administration

There are several reports showing evidence for the existence of high levels of prolactin (PRL) in alcoholic men and women. Alcohol-induced hyperprolactinemia has also been demonstrated in nonhuman primates and laboratory animals. Therefore, the clinical data as well as animal data suggest that ethanol consumption is a positive risk factor for hyperprolactinemia. In animal studies, it was found that chronic ethanol administration not only elevates plasma levels of PRL but also increases proliferation of pituitary lactotropes. Ethanol action on lactotropes involves crosstalk with estradiol-responsive signaling cascade or estradiol-regulated cell-cell communication. Additionally, it involves suppression of dopamine D2 receptors inhibition of G proteins and intracellular cyclic adenosine monophosphate (cAMP), modulation of transforming growth factor-beta (TGF-beta) isoforms and their receptors (TbetaRII), as well as factors secondary to TGF-beta actions, including production of beta-fibroblast growth factor (bFGF) from follicular-stellate cells. The downstream signaling that governs b-FGF production and secretion involves activation of the MAP kinase p44/42-dependent pathway. A coordinated suppression of D2 receptor- and TbetaRII receptor-mediated signaling as well as enhancement of bFGF activity might be critical for ethanol action on PRL production and cell proliferation in lactotropes.