Chronic Effects of Somatotropin Treatment in Vivo and in Vitro on Lipogenic Activity of Goat Adipose Tissue in a Glucose-Free Buffer During Acute Incubation

J. ŠKARDA

Institute of Animal Physiology and Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic

Received July 7, 1998
Accepted September 15, 1998

Summary
Young castrated male goats (n = 8) were used to investigate the effect of long-term treatment with recombinant methionyl bovine somatotropin in a sustained release vehicle (bST; 100 mg at seven-day intervals in a 147-day experiment) and chronic culture (24 h) of omental adipose tissue in the presence of various hormones on lipogenic responses to catecholamines during acute incubation (2 h) in a sodium acetate supplemented glucose-free buffer. The rate of fatty acid synthesis in freshly-prepared adipose explants was low and did not differ from those cultured in the absence of hormones for 24 h. Hormonal combination of insulin (17 nmol.l-1) plus cortisol (138 nmol.l-1) or insulin plus recombinant enterokinase linker bST (4.5 nmol.l-1) increased lipogenesis (P<0.05). Further addition of bST or cortisol decreased lipogenesis significantly (P<0.05) in the controls but not significantly in bST-treated animals. Cultured explants from either control or bST-treated animals showed significant inhibition of lipogenesis by both norepinephrine (10 m mol.l-1) and isoprenaline (10 m mol.l-1). BST treatment in vivo did not increase the responsiveness of cultured explants to norepinephrine in vitro, however, the responsiveness to isoprenaline(inhibition of lipogenesis) was greater in bST-treated animals than in the controls.

Key words
Goat - Adipose tissue - Somatotropin - Cortisol - Lipogenesis