Effects of central injection of Ghrelin on TSPO gene expression in the ovaries of rats (Rattus norvegicus) androgenized in Third day of birth

Abstract

Ghrelin exerts inhibitory effects on gonadotropins secretion. The product of TSPO gene is mainly found on the outer mitochondrial membrane and it is a key protein in the steroidogenesis pathway. It transports cholesterol in to mitochondria of organs that synthesize steroids. Treatment of neonatal female rats with testosterone propionate (TP) alters gonadotropin secretion patterns in the adulthood. In the present study the effects of central injection of ghrelin were investigated on the expression of TSPO gene in the ovaries of pubertal androgenized female rats. Twenty neonatal female rats were androgenized on the third day after birth by subcutaneous injection of 50μg TP and five neonatal female rats in one group was considered as controls. After puberty, the animals in four groups (n=5 in each group) received central injections of saline or different doses of ghrelin(2, 4 or 8μg). Also, five non-androgenied rats as control group received central injection of saline. The ovaries were removed bilaterally and frozen. TSPO gene expression levels was determined by semi quantitative RT-PCR. The mRNA levels of TSPO increased significantly in the ovaries of the androgenized rats compared to the controls. Ghrelin injections decreased significantly TSPO gene expression compared to the androgenized rats (P <0.05). Androgen may stimulate TSPO gene expression in the ovaries. Ghrelin may exert inhibitory effects on reproductive axis partly via reducing the expression of genes involved in the steroidogenesis.