Fatty acids turnover rates

Nobes, C.D., P.L. Lakin-thomas, and M.D. Brand (1989). The contribution of ATP turnover by the Na+/K+-ATPase to the rate of respiration of hepatocytes. Effects of thyroid status and fatty acids. Biochim. Biophys. Acta 976 241-245. 

From this discussion, it follows that the activity of the PDC tends to be directly associated with high rates of ATP turnover or high concentrations of pyruvate, that is, conditions during which the oxidative removal of glucose, lactate, and pyruvate is accelerated. In contrast, PDC activity tends to be inversely associated with diversion of these substrates toward gluconeoge-nesis. A reciprocal relationship exists in some tissues between the oxidation of carbohydrate and long-chain fatty acids that is mediated, in part, by the ratio of phosphorylated/unphos-phorylated PDC. This phenomenon, termed the glucose-fatty acid cycle, is best demonstrable... 

Q3 The thyroid hormones thyroxine and triiodothyronine have many metabolic effects. In adults they increase metabolic rate, oxygen and calorie consumption, stimulate carbohydrate metabolism and turnover of protein, deplete fat stores and increase catabolism of free fatty acids. Thyroid hormones stimulate heart rate and force and increase pulmonary ventilation, gastrointestinal motility and central nervous system (CNS) activity. Actions on the heart can result in an increased incidence of dysrhythmias. Thyroid hormones are critical for the normal growth and development of the infant, particularly in respect of skeletal growth and maturation of the CNS. 

Mutations in the active site of the enzyme can decrease the flavin-to-haem electron transfer rate to an extent that it is almost identical to the steady-state turnover rate of the enzyme (Noble et al., 1999). Also, problems with flavin fluorescence can be circumvented by studies of the haem domain of P450 BM3, and this has proven of great value for resonanee Raman characterisation of the haem site. One important finding from such studies has been that the active site of P450 BM3 is large enough to aeeommodate both a fatty acid and a large inhibitor molecule (metyrapone) simultaneously (Macdonald et al., 1996). 

Lipids have an adverse effect on carbohydrate metabolism under basal conditions. The infusion of 20% triglyceride emulsion with heparin during basal insulin and glucose turnover conditions resulted in a rise of plasma free fatty acids from 0.4 to 0.8 mmol/1 at a low rate of infusion (0.5 ml/minute for 2 hours) to between 1.6 and... 

Fatty Acid Concentrations and Their Turnover Rates in Phospholipids of Rat Whole Brain... 

A frying oil with a high FA content will smoke progressively at a lower temperature. Free fatty acid (FFA) content increases rapidly if heating is poorly controlled if the frying rate is insufficient to remove water from the food and, of course, if the turnover rate is kept above certain hours. 

Current research on changes in the stracture of the cytoplasmic membrane shows the involvement of 1) the composition of the fatty acids of the phospholipids like the cis/trans isomerization of unsaturated fatty acids 2) composition of phospholipid headgroups and 3) rate of turnover of membrane components. 

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