Effects of third cerebral injection of ghrelin on aromatase gene expression in the hypothalamus of androgenized female rats

Ghrelin exerts inhibitory effects on hypothalamus- pituitary- gonadal(HPG) axis. Aromatase is a key enzyme in the steroidogenesis pathway and it converts testosterone to the estradiol in the brain. In the present study the effects of the injection of ghrelin was investigated on aromatase gene expression in the hypothalamus of androgenized female rats. Twenty female Wistar rats were androgenized on the third day after birth by subcutaneous injection of 50 microgram testosterone propionate. Adult androgenized animals received third cerebral injection of saline, 2, 4 or 8 microgram ghrelin respectively. Also, five adult non-androgenized rats received third cerebral injection of saline as control group. The hypothalamic level of aromatase gene expression was determined using semi-quantitative PCR. Mean aromatase gene expression increased significantly in the hypothalamus of the androgenized rats compared to controls. Ghrelin decreased significantly aromatase gene expression compared to the androgenized rats. Ghrelin may inhibit the expression of genes involved in the steroidogenesis.