Considering that LPL is associated not only with the hydrolysis of triglyceride molecules found in plasma lipoproteins, chylomicrons, and VLDL [29], but also with adipogenesis, obesity, the energy balance, metabolic disorders, and abnormal regulation of body weight [30], the decreased inhibition of LPL exerted by testosterone after two weeks of castration may explain the weight loss observed in these animals. The gene discussed is LPL; the disease is obesity due to melanocortin 4 receptor deficiency.