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...

We sought to determine the effects of supplementary choline, carnitine and a combination of the two with or without exercise on serum and urinary carnitine and biochemical markers of fatty acid oxidation in healthy humans. Nineteen women were placed in three groups: 1) placebo, choline or carnitine preloading period of 1 wk followed by 2) supplementation with choline plus carnitine during wk 2-...

background: to determine any correlation between infertility and semen quality with concentrations of l-carnitine in human seminal plasma. methods: this case-control study performed in fatemieh hospital in hamadan, iran. seminal plasma of 72 infertile men and 80 men with proved fertility as a control group was investigated and l-carnitine level was determined using uv enzymatic test at 340 nm. ...

OBJECTIVES L-carnitine and dehydro-epiandrosterone (DHEA) independently promote mitochondrial energy metabolism. We therefore wondered if an age-related deficiency of L-carnitine or DHEA may account for the declining energy metabolism associated with age. METHODS we evaluated serum levels of L-carnitine and the sulphated derivative of DHEA (DHEAS) in cross-sectional study of 216 healthy adult...

Radioisotopic analyses for carnitine content were done on infant formula, formulas for tube feeding, food supplements, and chemically defined diets. The carnitine content of the diets depend on the protein source. Products whose main protein source is soy protein isolate, casein, or egg white solids contain 4 nmole carnitine per milliliter or less, with most of them containing undetectable amou...

BACKGROUND Ninety-five percent of the body carnitine pool resides in skeletal muscle where it plays a vital role in fuel metabolism. However, vegetarians obtain negligible amounts of carnitine from their diet. OBJECTIVE We tested the hypothesis that muscle carnitine uptake is elevated in vegetarians compared with that in nonvegetarians to maintain a normal tissue carnitine content. DESIGN F...