ABSTRACT
Apoptosis, the regulated destruction o f a cell, is characterized by biological and morphological changes and involves a large web o f integrating pathways and factors. Apoptosis is necessary to eliminate excess cells and cells that hinder development and hence the importance o f apoptotic pathways and apoptotic agents in removing adipocytes for the treatment o f obesity has been recently explored. Leptin was widely recognized for its ability to regulate adipose tissue mass by influencing food intake and energy expenditure. Recent findings, however, demonstrated that leptin treatment initiated apoptosis in adipose tissue. Leptin-induced adipocyte apoptosis was a surprising finding, as adipocytes were thought to be extremely stable; however, both pro-and anti-apoptotic effects o f leptin have been demonstrated in several cell types. In particular, anti-apoptotic effects have been shown in certain types o f cancer cells and are correlated with the presence o f leptin receptors. While leptin s effects on energy balance, including induction o f adipocyte apoptosis, are primarily mediated by the central nervous system, it is possible that anti-apoptotic effects o f leptin are mediated through autocrine or paracrine effects. In this chapter both anti-apoptotic and pro-apoptotic effects o f leptin in several cell types are reviewed.
