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M Farstad

Publications and source records attributed to M Farstad.

89 records · Page 5Linked to original sources
PubMed1978

Hydrolysis of long-chain fatty acyl-CoA in homogenates of human blood platelets: the existence of a platelet palmitoyl-CoA hydrolase.

The existence of a very active long-chain fatty acyl-CoA hydrolase in homogenates of human blood platelets is reported. The highest activity was found with palmitoyl-CoA as the substrate. Palmitoyl-CoA hydrolase activity was not found in intact platelets indicating that the enzyme is localized within the platelet membrane. No palmitoyl-CoA hydrolase activity was found in fasting plasma. Mg2+, Mn2+, Ca2+ and Triton X-100 inhibited the palmitoyl-CoA hydrolase activity. Sulphydryl reagents had no effect, whereas high concentrations of D- and L-carnitine inhibited the activity. Carnitine palmitoyltransferase did not interfere with the assay of palmitoyl-CoA hydrolysis as the activity of carnitine-palmitoyl hydrolase was less than 1% of the palmitoyl-CoA hydrolase activity.

Acyl Coenzyme A↗
PubMed1978

On the capacity of the beta-oxidation of palmitate and palmitoyl-esters in rat liver mitochondria.

The beta-oxidation of palmitate, palmitoyl-CoA and palmitoyl-L-carnitine proceeded at a high rate in isolated rat liver mitochondria. At high concentrations (100 nmol/mg protein) the oxidation of palmitate and palmitoyl-CoA was only partly carnitine dependent. All substrates were most rapidly oxidized in the presence of oxaloacetate and state 3 conditions. Succinate inhibited beta-oxidation especially in state 4 conditions. beta-Oxidation was faster in hypotonic than in isotonic medium both in state 3 and state 4 conditions. Hypertonicity inhibited beta-oxidation. The initial formation of palmitoyl-CoA from palmitate, CoA and ATP was faster than the oxidation of palmitate under identical conditions. The presence of bovine serum albumin inhibited the beta-oxidation, especially with palmitoyl-CoA or free palmitate as the substrates. Mitochondria contain a palmitoyl-CoA hydrolase which may influence the available intramitochondrial palmitoyl-CoA. The present results demonstrate no single rate limiting step in the beta-oxidation in vitro. Both the NADH/NAD ratio, competition for the respiratory chain, the level of ADP, binding of palmitoyl-CoA to extramitochondrial protein, and possibly intramitochondrial hydrolysis of palmitoyl-CoA all seem to influence the rate of beta-oxidation in vitro. It is suggested that in vivo the most important factor is the availability of acyl-CoA to the outer carnitine palmitoyl-transferase of the mitochondria.

Acyl Coenzyme A↗
PubMedDate not supplied

Effect of allopurinol on the concentration of endogenous glutathione in hepatocytes after an hour of normothermic liver ischemia.

OBJECTIVE: To find out whether oxygen free radical liberated by activation of xanthine oxidase change the tissue concentration of glutathione. DESIGN: Controlled study. MATERIAL: 42 male Wistar rats. INTERVENTION: Laparotomy, induction of ischemia, and reperfusion. 27 rats were treated with allopurinol (to inhibit xanthine oxidase) and the remaining 15 acted as controls. MAIN OUTCOME MEASURES: Concentrations of reduced glutathione, oxidized glutathione, and total glutathione in hepatocytes, blood, and bile. RESULTS: Concentration of reduced and total glutathione in hepatocytes decreased significantly during reperfusion and oxidized glutathione was unchanged in all groups. Total glutathione in peripheral venous blood was reduced by half during the period of ischemia and increased gradually during reperfusion whereas the concentration of total glutathione in bile decreased appreciable during reperfusion. Production of bile improved significantly during reperfusion in the group treated with allopurinol compared with the control group. CONCLUSION: Xanthine oxidase may not be the main source of production of oxygen free radicals as allopurinol did not affect the hepatic concentration of glutathione during reperfusion.

Allopurinol↗