SEX-SPECIFIC CHANGES IN PREOPTIC REGULATORY FACTOR-I AND PREOPTIC REGULATORY FACTOR-II MESSENGER-RNA EXPRESSION IN THE RAT-BRAIN DURING DEVELOPMENT

Preoptic regulatory factor-1 (Porf-1) and Preoptic regulatory factor-2 (Porf-2) are two novel peptide genes which are expressed in the centr al nervous system. Expression is modified by age and by hormones of th e reproductive system. In this study nuclease protection assays were e mployed to investigate Porf-1 and Porf-2 mRNA expression in the cerebr al cortex (CC), hippocampus (HIPP), preoptic area (POA) and medial bas al hypothalamus (MBH) of male and female rats, aged 15, 30 and 60 days . Porf-1 and Porf-2 mRNA expression tended to decrease from 15 to 60 d ays, with two exceptions. Porf-2 in the hippocampus of female rats, an d Porf-2 in the MBH of the male rats, were found instead to increase w ith age. There were distinctive sex differences in porf-1 and porf-2 g ene expression. Consistently higher mRNA levels were measured for both genes in the POA of female rats at all ages examined, and this differ ence reached statistical significance for Porf-1 at the age of 60 days . In contrast, levels of Porf-2 mRNA were higher in MBH of male than f emale rat MBH at 15 days, and Porf-1 mRNA was substantially more abund ant in male than in female rat MBH at 30 and 60 days of age. These res ults indicate that there is sexual dimorphism and regional specificity in the developmental expression of these genes.