Carnitine and dehydroepiandrosterone sulfate induce protein synthesis in porcine primary osteoblast-like cells

Age-related bone loss eventually leads to osteopenia in men and women. The etiology of age-related bone loss is currently unknown; however, decreased osteoblast activity contributes to this phenomenon. In turn, osteoblast pro liferation and function is dependent on energy production, thus the loss of energy production that occurs with age may account for the deficient osteo blast activity. Carnitine and dehydroepiandrosterone-sulfate (DHEAS), both of which decline with age, promote energy production through fatty acid met abolism. Thus, we hypothesized that carnitine and DHEAS would increase oste oblast activity in vitro. Accordingly, we measured the effect of carnitine and DHEAS on palmitic acid oxidation as a measure of energy production, and alkaline phosphatase (ALP) activity and collagen type I (COL) as indices o f osteoblast function in primary porcine osteoblast-like cell cultures. Car nitine (10(-3) and 10(-1) M) but not DHEAS (10(-9), 10(-8), and 10(-7) M) i ncreased carnitine levels within the cells. Carnitine alone and in combinat ion with DHEAS increased palmitic acid oxidation. Both carnitine and DHEAS alone and in an additive fashion increased ALP activity and COL levels. The se results demonstrate that in osteoblast-like cells in vitro, energy produ ction can be increased by carnitine and osteoblast protein production can b e increased by both carnitine and DHEAS. These data suggest that carnitine and DHEAS supplementation in the elderly may stimulate osteoblast activity and decrease age-related bone loss.