The effect of temperature and β-adrenergic agonist (BAA) on in vitro rates of fatty acid synthesis and catalytic activity of acetyl-CoA carboxylase (ACC) and fatty acid synthase (FAS) was examined in wether lambs after 5 weeks at either 0 or 20°C. Feeding BAA increased (P<0.05) rate of fatty acid synthesis by 38% in subcutaneous adipose (SC) tissue from cold-acclimated animals but the rate decreased (P<0.05) by 27% in SC tissue from warm-acclimated animals. In mesenteric fat (MS), BAA increased (P<0.05) fatty acid synthesis in the cold environment. In perirenal (PR) fat, rate of fatty acid synthesis was reduced (P<0.05) by 20% by BAA in the warm but had no effect in the cold. Activity of ACC in longissimus muscle was depressed (P<0.05) when BAA was fed in the warm environment. In adipose tissues BAA reduced (P<0.05) ACC activity in the warm, but reduced activity in the cold was limited to SC tissue. In PR tissue FAS activity was reduced (P<0.05) in the cold environment, while BAA increased FAS activity in the warm environment. Western blot analysis showed two isoforms of ACC with MW of 280 000 and 265 000 Da in longissimus muscle whereas only one isoform was recognized in each of Biceps femoris (280 000 Da) and adipose tissues (265 000 Da). Feeding BAA in the cold environment reduced (P<0.05) ACC and FAS immunoprotein expression in both MS and PR adipose tissues. The studies indicate that the effect of BAA on fatty acid synthesis and lipogenic enzymes is influenced by acclimation temperature. Copyright (C) 2000 Elsevier Science Inc.
|Original language||English (US)|
|Number of pages||13|
|Journal||Comparative Biochemistry and Physiology - C Pharmacology Toxicology and Endocrinology|
|State||Published - Feb 2000|
Bibliographical noteFunding Information:
The authors are grateful for the excellent technical assistance of Charlane Gorsak, Clint Lysgaard, Steve Melnyk and Brenda Tchir in conducting these experiments. L-644,969 was donated by Dr C.H. Chang, Merck Research Laboratories, Rahway, NJ. Funding for the studies was provided by the Natural Sciences and Engineering Research Council of Canada.
- Acetyl-CoA carboxylase
- Environmental temperature
- Fatty acid synthase
- β-Adrenergic agonist