Leptin ? obesity gene product was discovered in 1994. It is synthesized predominantly in the white adipose tissue , but also in the ovary , placenta and mammary gland during lactation. Therefore , it is believed that leptin is involved in fetal and neonatal development . The main target of the leptin regulation of energy balance and reproductive function are the nucleus of the hypothalamus , which modifies the activity of the hypothalamic- pituitary . In genetically obese and infertile mice ( ob / ob) exogenous leptin restores fertility in both females and males.