In this study, we sought to identify the transporters that mediate the uptake of L-carnitine and acetyl-L-carnitine in cultured rat cortical astrocytes. L-[(3)H]carnitine and acetyl-L-[(3)H]carnitine uptake were both saturable, and mediated by a single Na(+)-dependent transport system. Uptake of both was inhibited by L-carnitine, D-carnitine, acetyl-L-carnitine and various organic cations. Acyl...

Growth performance, food efficiency and body composition of pikeperch (Sander lucioperca) were investigated with 1 or 2 g/kg L-carnitine added to the diet. Control diet did not contain L-carnitine. Two hundred pikeperch fingerlings (1.63 g, mean weight) were stocked in each 1 m3 concrete tank and fed equally 6 meals per day for 6 weeks. Higher increment in body weight (5.92 ± 0.37 g), the ...

The metabolic function of carnitine in the fatty acid oxidase-deficient flight muscle of the blowfly, Phormia regina, was investigated. Mitochondria from flies did not oxidize pahnitate or hexanoate in the presence of adenosine triphosphate, coenzyme A, carnitine, and serum albumin. Pahnitoyl carnitine was oxidized at an extremely slow rate, QOz of 20. The rate of synthesis of the carnitine est...

Carnitine has important roles in skeletal muscle bioenergetics. Skeletal muscle carnitine deficiency is associated with profound impairment of muscle function. It has thus been natural to ask if carnitine supplementation can improve skeletal muscle function and athletic performance in healthy individuals. Oral carnitine doses of several grams cause no significant clinical toxicity, further enco...

have been reported by several authors [2,3,6 ]. The Introduction high total serum concentration of carnitine results predominantly from an increase in -carnitine esters, Recombinant human erythropoietin (rhEpo) is widely i.e. acylcarnitine. As a result of the reduction in free used for correction of anaemia in patients with endcarnitine, the ratios of free/total carnitine and free stage renal ...

PURPOSE Pharmacokinetics and effects on skeletal muscle and physical performance of oral acetylcarnitine and propionylcarnitine are not well characterized. We therefore investigated the influence of oral acetylcarnitine, propionylcarnitine, and carnitine on body carnitine homeostasis, energy metabolism, and physical performance in mice and compared the findings to non-supplemented control anima...

Malonyl-CoA significantly increased the Km for L-carnitine of overt carnitine palmitoyltransferase in liver mitochondria from fed rats. This effect was observed when the molar palmitoyl-CoA/albumin concentration ratio was low (0.125-1.0), but not when it was higher (2.0). In the absence of malonyl-CoA, the Km for L-carnitine increased with increasing palmitoyl-CoA/albumin ratios. Malonyl-CoA di...

Carnitine, a structurally choline-like metabolite, has been used to increase athletic performance, although its effects on neuromuscular transmission have not been investigated. It is present in skeletal muscle and its plasma levels are about 30 to 90 micro M. Using rat phrenic nerve diaphragm preparations indirectly and directly stimulated with high rate pulses, D-carnitine (30 and 60 micro M)...

The existence of a cardiac carnitine binding protein was demonstrated using an in vitro binding assay. The binding activity was solubilized with Triton X-100 from the pellet following a 59,000 X g centrifugation of rat ventricular homogenates. Preincubation at temperatures above 40 degrees C or treatment with pronase significantly reduced the binding activity, suggesting that the activity was t...

Prodrugs that liberate pivalate (trimethylacetic acid) after hydrolysis have been developed to improve the bioavailability of therapeutic candidates. Catabolism of pivalate released by activation of a prodrug is limited in mammalian tissues. Pivalate can be activated to a coenzyme A thioester in cells. In humans, formation and urinary excretion of pivaloylcarnitine generated from pivaloyl-CoA i...