AR and obesity due to melanocortin 4 receptor deficiency: In the same way, global AR knockout strategy or hepatic-, muscle-, or pancreas-specific KO results in male obesity with decreased energy expenditure, hepatic steatosis, and insulin resistance [55]; but, male mice lacking AR in adipose tissue do not exhibit obesity or enhanced fatness probably due to increased estradiol levels measured in adipose tissue [56] (Table 1).