Leptin enhances ovulation and attenuates the effects produced by food restriction

The aims of this study were to investigate the effects of chronic feed deprivation on the ovulatory process, and to assess whether leptin administration is able to alter these effects. Prepuberal rats subjected to food restriction and primed with gonadotrophins were used. Body and ovarian weights were significantly decreased in proportion to the severity of the food restriction. Only the most severe feed deprivation was able to inhibit the ovulation rate. Either buffer or leptin was daily administrated to prepuberal rats fed either ad libitum or with a severe food restriction. Serum progesterone, ovulation rate and ovarian prostaglandin E2 were reduced in rats subjected to food restriction and stimulated by daily administration of leptin in rats fed ad libitum. Negative effects produced by a severe food restriction were partially reversed by chronic administration of leptin. The ovarian endothelium nitric oxide synthase expression was strongly inhibited in rats with food restriction and once again, leptin administration reversed this effect. In summary, the ovulatory process was significantly inhibited in response to a severe decrease in food intake, at least in part, to the direct or indirect impairment of some ovarian factors production as prostaglandins and nitric oxide. Chronic treatment with leptin enhanced the ovulatory process in comparison with control animals, and partially prevented these negative effects produced by a severe malnutrition.