Affordable Access

Publisher Website

Increased hepatic pyruvate dehydrogenase kinase activity in fed hyperthyroid rats: studies in vivo and with cultured hepatocytes

Authors
Journal
Molecular and Cellular Endocrinology
0303-7207
Publisher
Elsevier
Publication Date
Volume
119
Issue
2
Identifiers
DOI: 10.1016/0303-7207(96)03817-8
Keywords
  • Hepatocytes
  • Insulin Resistance
  • Fatty Acids
  • Tri-Iodothyronine

Abstract

Abstract Experimental hyperthyroidism induced by the administration of tri-iodothyronine (T3; 100 μ g 100 g body wt; 3 days) increased plasma non-esterified fatty acids in the fed state in the rat. At the same time, hepatic PDH kinase responded with a persistent (1.6-fold) increase in activity. The exposure of hepatocytes from fed euthyroid rats to T3 (100 nM) in culture for 21 h increased PDH kinase activity to an extent comparable to that observed in vivo in response to hyperthyroidism. The in vitro increase in PDH kinase activity was suppressed by insulin (100 μU/ml) and by inhibition of mitochondrial fatty acid oxidation. The results demonstrate a direct hepatic action of T3 to increase PDH kinase activity, which is mediated by intramitochondrial fatty acyl-CoA or a product of β-oxidation, and facilitated by hepatic insulin resistance.

There are no comments yet on this publication. Be the first to share your thoughts.