Enhanced food intake by progesterone-treated female rats is related to changes in neuropeptide genes expression in hypothalamus.

INTRODUCTION Progesterone-treated females eat more food, but the mechanism underlying this effect is not well understood. The aim of the study was to analyse the effect of progesterone on neuropeptide genes expression in rat hypothalamus. MATERIAL AND METHODS Experiments were carried out on female and male Wistar rats. Animals were treated with progesterone (100 mg per rat) for 28 days. NPY and CART mRNA levels in hypothalamus were quantified by real-time PCR. The serum progesterone concentration was determined by radioimmunoassay. RESULTS Progesterone administration to females caused an increase in food intake, body mass, and white adipose tissue mass. Elevated circulating progesterone concentration up-regulated NPY and down-regulated CART genes expression in hypothalamus of females. In males, elevated blood progesterone concentration had no effect on food intake, body and fat mass and on the neuropeptide genes expression in hypothalamus. Moreover, administration of progesterone in females resulted in decrease of PR mRNA level in hypothalamus. No effect of progesterone administration on PR mRNA level in hypothalamus of males was found. CONCLUSIONS The changes in neuropeptide genes expression in hypothalamus may lead to stimulation of appetite and might explain the observed increase in food intake, body and adipose tissue mass in progesterone-treated females.