Progesterone receptor isoforms expression in the prepuberal and adult malerat brain

Progesterone receptor (PR) isoforms expression was determined in several re gions of the prepuberal and adult mate rat brain by using reverse transcrip tion coupled to polymerase chain reaction, Rats under a 14:10-h light-dark cycle, with lights on at 0600 h were used, We found that in the hypothalamu s of prepuberal animals the expression of both PR isoforms was similar, whe reas PR-A expression was higher than that of PR-B in adults. In the cerebel lum PR-B expression was predominant in both prepuberal and adult rats. In b oth ages PR-A and PR-B exhibited a non-significant tendency to be predomina nt in the hippocampus and the preoptic area respectively. In the frontal co rtex and the olfactory bulb PR isoforms were expressed at a similar level. These results indicate a differential expression pattern of PR isoforms in the male rat brain and suggest that the tissue-specific expression of PR-A and PR-B is important for the appropriate response of each cerebral region to progesterone. (C) 2001 Elsevier Science Inc.