Tumor necrosis factor alpha differentially regulates beta-endorphin concentrations and proopiomelanocortin RNA in the anterior and neurointermediate pituitary in vivo

We analyzed the effect of tumor necrosis factor alpha (TNF-alpha) on beta-endorphin concentrations and proopiomelanocortin mRNA in the rat anterior and neurointermediate pituitaries. The intraperitoneal injection of 5 micrograms/kg TNF-alpha decreases beta-endorphin in neurointermediate pituicytes 4, 8 and 24 h after the treatment without affecting proopiomelanocortin (POMC) RNA. In contrast, in the anterior pituitary 4 h after the injection of the cytokine, POMC RNA was decreased while the peptide content was increased. These effects can be relevant to the modulation of the pituitary-adrenal axis and immune responses in conditions, such as infections, in which TNF levels are increased.