Interaction of the effects between vitamin D receptor polymorphism and exercise training on bone metabolism

Abstract

Bone metabolism is strongly influenced by heredity and environmental factors. To investigate interaction of the effects between vitamin D receptor polymorphism by Fok I and resistance exercise training on bone metabolism, young male subjects with FF genotype (F, n = 10) and Ff or ff genotypes (f, n = 10) followed 1 mo of weight training, and changes in bone metabolism were compared. An additional 14 subjects served as a sedentary control. Biomarkers of bone formation, bone-specific alkaline phosphatase, and osteocalcin were significantly increased by training in both F and f groups. 1, 25-Dihydroxyvitamin D(3), known to upregulate bone formation, was also increased by the training in the f but not in the F group. Bone resorption assessed by cross-linked NH(2)-terminal telopeptide of type I collagen was significantly suppressed by the training, and the decrease in F was greater and longer lasting than that in f group. In conclusion, stimulation of bone formation and suppression of bone resorption occurred within 1 mo in young men. Despite a significant increase in 1,25-dihydroxyvitamin D(3) in the f group but not in the F group, the response of bone metabolism to the training in the F was similar to or greater than that in f group, suggesting a functional difference between vitamin D receptor genotypes f and F.

Mechanical loading-induced gene expression and BMD changes are different in two inbred mouse strains

“…A number of studies have shown that mechanical loading promoted bone formation (BF) in the modeling skeleton and that removal of this stimulus resulted in a reduction in bone mass (1,9,13,28,29). In addition, recent studies have also shown that the increase in bone mass was variable in different subjects subjected to the same amount of mechanical stress, with some exhibiting a robust osteogenic response and others responding more modestly (8,24,26). We and others found evidence that this variation in response to mechanical loading is, in large part, genetically determined (12,13,19).…”

Mechanical modulation of molecular signals which regulate anabolic and catabolic activity in bone tissue

“…Decreases in functional loading, which occur under conditions, such as spaceflight or bedrest, suppresses osteoblast activity while elevating osteoclastic activity [Turner, 2000], resulting in a net loss of bone [Alexandre et al, 1988;Judex et al, 2004]. Conversely, specific increases in load bearing, as in the form of exercise, can stimulate osteoblastic activity while suppressing osteoclast recruitment and activity [Judex and Zernicke, 2000;Tajima et al, 2000], resulting in net improvements in both bone quantity and quality Judex et al, 2003].…”

Growing a Healthy Skeleton: Exercise—the Primary Driving Force

“…Variation in the vitamin D receptor genotype has been associated with variance in the osteogenic responses to hours of physical activity in children (Nakamura et al 2002;Omasu et al 2004) and bone metabolism responses following strenuous resistance training in young male adults (Tajima et al 2000). Despite this, there is some indication that variation in several specific genes may influence an individual's response to loading.…”