ABSTRACT
Leptin, a 16-kilodalton protein secreted by the adipose tissue in proportion to the
amount of energy stored in adipose tissue, conveys to the hypothalamus information
on energy homeostasis and regulates reproductive function. In addition, there is accumulating
evidence that leptin produced by placental or fetal tissues acts through specific
leptin receptors to regulate fetal growth and development. Although leptin levels
are correlated with insulin and insulin-like growth factor (IGF)-1 levels, observational
studies in humans indicate that its effects on fetal growth are independent of these
axes and of adiposity. The extent to which leptin per se mediates the fetal growth
and developmental abnormalities associated with disease states such as diabetes, hypoxia,
or preeclampsia remains to be fully clarified by future studies in humans. It is hoped
that clarification of these mechanisms may provide novel therapeutic approaches.
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