Inhibition of carnitine palmitoyltransferase I by hepatocyte swelling.
Incubation of hepatocytes under conditions known to increase their volume, i.e. with amino acids (glutamine, proline) or in hypo-osmotic medium, decreased carnitine palmitoyl-transferase I (CPT-I) activity. This effect of hepatocyte swelling was antagonized by okadaic acid and dibutyryl-cAMP. Physiological concentrations of glutamate inhibited CPT-I activity in digitonin-permeabilized hepatocytes but not in isolated mitochondria. Results suggest that the amino acid-induced inhibition of CPT-I shares a common mechanism with the amino acid-induced stimulation of acetyl-CoA carboxylase and glycogen synthase [(1993) Eur. J. Biochem. 217, 1083-1089].
Guzmán
M
M
Department of Biochemistry and Molecular Biology I, Faculty of Chemistry, Complutense University, Madrid, Spain.
Velasco
G
G
Castro
J
J
Zammit
V A
VA
D000103:Acetyl-CoA Carboxylase / Q000378:metabolism; D000596:Amino Acids / Q000494:pharmacology; D000818:Animals; D003994:Bucladesine / Q000494:pharmacology; D002334:Carnitine O-Palmitoyltransferase / Q000037:antagonists & inhibitors*; D002463:Cell Membrane Permeability; D048429:Cell Size; D004072:Digitonin; D004988:Ethers, Cyclic / Q000494:pharmacology; D005971:Glutamates / Q000494:pharmacology; D018698:Glutamic Acid; D005973:Glutamine / Q000494:pharmacology; D006006:Glycogen Synthase / Q000378:metabolism; D007038:Hypotonic Solutions; D008099:Liver / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology; D008297:Male; D019319:Okadaic Acid; D051381:Rats; D017208:Rats, Wistar
D000596:Amino Acids; D004988:Ethers, Cyclic; D005971:Glutamates; D007038:Hypotonic Solutions; D005973:Glutamine; D019319:Okadaic Acid; D018698:Glutamic Acid; D003994:Bucladesine; D002334:Carnitine O-Palmitoyltransferase; D006006:Glycogen Synthase; D000103:Acetyl-CoA Carboxylase; D004072:Digitonin