Effect of Somatotropin on
Adipose Tissue Net Glucose-Stimulated Lipogenesis in Young Goats
J. ŠKARDA
Institute of Animal Physiology and Genetics,
Academy of Sciences of the Czech Republic, Prague, Czech
Republic
Received June 4, 1998
Accepted October 9, 1998
Summary
Net glucose-stimulated lipogenesis (NGSL: the rate of
lipogenesis in the presence of glucose minus the rate of
lipogenesis in the absence of glucose) in omental adipose tissue
explants from young castrated male goats was evaluated in
control animals (n = 3; placebo-treated) and in animals treated
with the sustained release of recombinant bovine somatotropin (n
= 4; bST; 100 mg at 7-day intervals in a 147 days lasting
experiment). The rate of fatty acid synthesis was determined in
acute incubations in both freshly prepared and chronically
cultured explants. Adipose explants remained metabolically
active and retained their ability to respond to hormones when
maintained in a tissue culture medium. NGSL in explants cultured
for 24 h in the presence of insulin alone or bST alone, was
non-significantly increased (more in the controls) and decreased
(more in bST-treated animals), respectively. However, cortisol
alone decreased (P<0.05) NGSL in explants from both control and
bST-treated animals. In tissues from bST-treated animals,
cortisol acted synergistically with insulin to produce a higher
rate of NGSL than that observed in cultures with insulin alone.
bST inhibited insulin plus cortisol-stimulated lipogenesis
significantly (P<0.05) in explants from bST-treated animals but
non-significantly in control animals. The rates of NGSL were
decreased (P<0.05) by catecholamines in explants from both
control and bST-treated animals. Norepinephrine (NE) and
isoprenaline (ISO) were equally effective in the controls,
whereas isoprenaline was more effective than norepinephrine in
bST-treated animals.
Key words
Goat · Adipose tissue · Lipogenesis · Somatotropin ·
Catecholamines
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