Rapid induction of parathyroid hormone-like peptide gene expression by sodium butyrate in a rat islet cell line.

The PTH-like peptide (PLP) gene is expressed in a diverse number of normal and neoplastic cell types, and induction of PLP gene expression has been observed after the induction of cellular differentiation. The differentiation of islet cells can be studied in vitro, after the exposure of rat islet cell lines to sodium butyrate. The present work found that rat RIN 1056A islet cells express the PLP gene and treatment with sodium butyrate resulted in rapid (detectable by 30 min) induction of PLP gene expression. PLP gene expression was rapidly and transiently induced by serum and cycloheximide, but the butyrate induction of PLP mRNA transcripts was not dependent on serum or new protein synthesis. Dexamethasone inhibited PLP gene expression and blocked the butyrate induction of PLP mRNA transcripts. The rapid induction of PLP gene expression after the exposure of islet cells to sodium butyrate, serum, and cycloheximide suggests that PLP may be a member of a class of early response genes involved in the regulation of cellular growth or differentiation.