Acute effects in vivo of anti-insulin serum on rates of fatty acid synthesis and activities of acetyl-coenzyme A carboxylase and pyruvate dehydrogenase in liver and epididymal adipose tissue of fed rats

Abstract

Plasma insulin concentrations in fed rats were altered acutely by administration of glucose or anti-insulin serum. Rates of fatty acid synthesis in adipose tissue and liver were estimated from the incorporation of 3H from 3H2O. In the adipose tissue dehydrogenase and acetyl-CoA carboxylase were evident. In liver, although changes in rates of fatty acid synthesis were found, the initial activity of pyruvate dehydrogenase did not alter, but small parallel changes in acetyl-CoA carboxylase activity were observed.

Erk regulation of pyruvate dehydrogenase flux through PDK4 modulates cell proliferation

“…One possible mechanism by which the reduction in PDH flux could affect proliferation is through reduced de novo lipogenesis, as fatty acid synthesis is critical for the production of new membrane during cell growth and proliferation. Indeed, PDH flux has been previously shown to correlate with lipogenesis (Stansbie et al 1976;Munday and Williamson 1981;Holness and Sugden 1990;Choi et al 2010) and we observed a 50%-65% decrease in the relative level of de novo lipogenesis in our MCF-10A models. Glucose-derived carbons, metabolized by PDH, are considered to be the primary source of AcCoA for lipogenesis in mammalian cells (Hatzivassiliou et al 2005).…”

Effect of starvation and insulin in vivo on the activity of the pyruvate dehydrogenase complex in rat skeletal muscles

“…This may mean that the PDH complex in muscle and BAT exhibits different insulin sensitivities, or that the time period of exposure to insulin has to be greater in the skeletal muscles than BAT for the same effect to be observed. The time of exposure and dose of insulin used in these experiments have previously been shown to be sufficient to elevate PDH complex activity in white adipose tissue [19].…”

Lipid metabolism in cancer cachexia

“…For time points beyond time zero the fat pad was gently returned to the abdominal cavity and the wound was clipped. At specified time points animals were sacrificed, tissues were removed and the concentration of labelled lipids determined by the methods of Stansbie et al (1976).…”

“…The complete gastrointestinal tract was removed and homogenised in 5 ml of 3% (w/v) HC104. Lipids were extracted from organs and blood by the method of Stansbie et al (1976). The extracted fatty acids were dissolved in Optiphase scintillation fluid and the radioactivity determined as above.…”