Plasma concentrations of vitamin D metabolites in puberty: effect of sexual maturation and implications for growth.

To relate the vitamin D metabolism in puberty to sex, sexual maturation, and, indirectly, to growth velocity and cessation of growth, the plasma level of 25-hydroxy vitamin D, 1,25-dihydroxyvitamin D [1,25-(OH)2D], 24,25-dihydroxyvitamin D [24,25-(OH)2D], and 25,26-(OH)2D were measured in 191 adolescents representing all stages of puberty. In girls, 1,25-(OH)2D3 increased from age 11 yr to a peak at 12 yr of age (P less than 0.0005) and then decreased. In boys, the increase occurred between 13--14 yr of age (P less than 0.005), with a subsequent decline. When the 1,25-(OH)2D concentrations were related to the stage of puberty, the girls showed a maximal increase between stages 1 and 2 (P less than 0.0005), with a peak at stage 3, whereas the boys had a significant increase from stage 2 to a peak at stage 3 (P less than 0.01). In both sexes, there were subsequent significantly decreasing values to stage 4 through stage 5. The ratio of 24,25-(OH)2D to 25-hydroxyvitamin D varied inversely with the 1,25-(OH)2D concentration, with the lowest value at age 12 yr in both sexes, followed by a gradual increase to a plateau at age 15 yr in girls and 17 yr in boys. It appears that the hormones of the vitamin D system add another dimension to the endocrinology of growth and puberty.