Roles of leptin, adiponectin and resistin in the transcriptional regulation of steroidogenic genes contributing to decreased Leydig cells function in obesity.

The increase in obesity rate is a major public health issue associated with increased pathological conditions such as type 2 diabetes or cardiovascular diseases. Obesity also contributes to decreased testosterone levels in men. Indeed, the adipose tissue is an endocrine organ which produces hormones such as leptin, adiponectin and resistin. Obesity results in pathological accumulations of leptin and resistin, whereas adiponectin plasma levels are markedly reduced, all having a negative impact on testosterone synthesis. This review focuses on current knowledge related to transcriptional regulation of Leydig cells' steroidogenesis by leptin, adiponectin and resistin. We show that there are crosstalks between the regulatory mechanisms of these hormones and androgen production which may result in a dramatic negative influence on testosterone plasma levels. Indeed leptin, adiponectin and resistin can impact expression of different steroidogenic genes such as Star, Cyp11a1 or Sf1. Further investigations will be required to better define the implications of adipose derived hormones on regulation of steroidogenic genes expression within Leydig cells under physiological as well as pathological conditions.