The body mass index, and especially the lean/fat tissue ratio, are determinants 
of female fertility. In 1996, it was claimed that leptin might be the "missing 
link" between fat and reproduction. Leptin belongs to the adipokine family, 
which also contains adiponectin and resistin. Leptin and resistin impair insulin 
sensitivity, whereas adiponectin enhances it. Leptin is a potent stimulator of 
central GnRH and gonadotropin secretion, and, paradoxically, a potent inhibitor 
of ovarian steroidogenesis. The central roles of adiponectin and resistin are 
less clear. In the ovary, adiponectin stimulates steroidogenesis by granulosa 
cells. Recent data point to the existence of a distinct lipid metabolism in the 
ovary. Its role in female reproduction will provide an exciting field of 
research in coming years.