Effects of catecholamines in vitro on lipogenesis in cultured adipose tissue from young goats.

Abstract

Freshly prepared and cultured perirenal and omental adipose tissue explants were used to investigate the effect of age and hormones on lipogenesis in young goats. Perinatal (1-2 days of age) and older (24-32 days of age) male goats were used. Adipose explants were cultured (24 h) in the presence of insulin, cortisol and recombinant bovine growth hormone (bST) and subsequently incubated (2 h) in a glucose-free buffer containing (14C)-acetate in the presence or absence of noradrenaline (Ne) and isoprenaline (Iso) to measure tissue lipogenic responses to hormones added to the culture medium and to measure the responsiveness to catecholamines. Inclusion of hormones in the culture medium did not change lipogenesis during subsequent acute incubation in glucose-free buffer in both perirenal and omental adipose tissue from perinatal goats. On the other hand, in perirenal explants from older animals, insulin alone or insulin plus cortisol increased (P < 0.05) and cortisol alone decreased (P < 0.05) the rate of fatty acid synthesis. When perirenal explants were cultured in the presence of insulin plus cortisol plus bST, the rates of lipogeneses were lower (P < 0.05) than those in cultures with insulin plus cortisol. A similar pattern of the effects of hormones on the rates of fatty acid synthesis was also seen in omental explants; however, these effects were not significant. In vitro rates of lipogeneses were decreased (P < 0.05) by Ne but not Iso in freshly prepared omental explants of both perinatal and older animals and in freshly prepared perirenal explants of older animals. In cultured perirenal explants of both perinatal and older animals the mean values of lipogenesis were decreased (P < 0.05) by both Ne and Iso. However, in cultured omental explants both catecholamines were effective (P < 0.05) in older but not in perinatal animals.