Effect of sex on lipogenic activity in swine adipose tissue

Adipose tissue was obtained from male, female and male pigs castrated either at birth, 2 or 4 mo of age. Pigs were biopsied at 11 and 20 wk of age to obtain adipose tissue samples. Lipogenic capacity was assessed by measurement of in vitro glucose incorporation into lipids of adipose tissue slices. At 20 wk of age, males were less fat than females or males castrated either at birth or 20 mo of age. Adipocyte volume at 20 wk of age was smaller in males, females and recently castrated males (4 mo) than males castrated at birth or 2 mo of age. Lipogenic rate at 20 wk of age was lower in males than in castrated pigs; females had intermediate lipogenic rates. The results provide a partial metabolic explanation for the difference in subcutaneous fat deposition in the sexually diverse groups. There was no effect of estradiol-17 beta or testosterone in vitro on adipose tissue lipogenesis, suggesting that sex hormone effects in vivo may not be involved in short-term regulation of lipogenesis.