Effects of volatile fatty acids on propionate metabolism and gluconeogenesis in caprine hepatocytes

J Dairy Sci. 1987 Dec;70(12):2504-10. doi: 10.3168/jds.S0022-0302(87)80318-1.

Abstract

Isolated caprine hepatocytes were incubated with fatty acids of various chain lengths. Short-chain fatty acids effects on rates of gluconeogenesis and oxidation from [2-14C]propionate were determined. Additions of glucose (2.5 mM) had no effect on hepatic [2-14C]propionate metabolism in the presence and absence of amino acids. A complete mixture of amino acids increased label incorporation from [2-14C]propionate into [14C]glucose by 22%. Butyrate inhibited [2-14C]propionate metabolism and increased the apparent Michaelis constant for [2-14C]propionate incorporation into [14C]glucose from 2.4 +/- 1.5 to 5.6 +/- .9 mM. Butyrate's effects on propionate were similar in the presence and absence of L-carnitine (1 mM). Isobutyrate, 2-methylbutyrate, and valerate (1.25 mM) had no effect on [14C]glucose production but decreased 14CO2 production to 57, 61, and 54% of the control [2-14C]propionate (1.25 mM). This inhibition on 14CO2 production was not competitive. Isovalerate had no effect on either [2-14C]propionate incorporation into glucose or CO2. An increase in ratio of [14C]glucose to 14CO2 from [2-14C]propionate demonstrated that short-chain fatty acids other than butyrate do not inhibit gluconeogenesis from propionate. In addition, fatty acids that generate a net synthesis of intracellular oxaloacetate may partition propionate carbons toward gluconeogenic rather than oxidative pathways in goat hepatocytes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Butyrates / pharmacology
  • Carnitine / pharmacology
  • Fatty Acids, Volatile / pharmacology*
  • Gluconeogenesis / drug effects*
  • Goats / metabolism*
  • In Vitro Techniques
  • Isobutyrates
  • Liver / cytology
  • Liver / drug effects
  • Liver / metabolism*
  • Male
  • Propionates / metabolism*
  • Valerates / pharmacology

Substances

  • Butyrates
  • Fatty Acids, Volatile
  • Isobutyrates
  • Propionates
  • Valerates
  • isobutyric acid
  • 2-methylbutanoic acid
  • Carnitine