Matsuoka L Y, Wortsman J, Haddad J G, Kolm P, Hollis B W
Department of Dermatology, Jefferson Medical College, Philadelphia, PA 19107.
Arch Dermatol. 1991 Apr;127(4):536-8.
The varying epidermal melanin content that produces racial pigmentation determines the number of photons that reach the lower (malpighian) cellular layers, where vitamin D3 synthesis takes place. We investigated the effect of racial pigmentation on vitamin D3 formation, stimulating the process with a fixed dose of UVB radiation (wavelengths, 290 to 320 nm). Vitamin D nutritional status was further assessed measuring serum 25-hydroxyvitamin D and the most active serum metabolite, 1,25-dihydroxyvitamin D. Experimental subjects were young (third decade of life) and healthy, representing the white, Oriental (East Asian), Indian (South Asian), and black races. Basal serum vitamin D3 levels were similar among groups, ranging from 2.3 +/- 0.6 nmol/L (mean +/- SEM) for blacks to 3.4 +/- 1.0 nmol/L for Indians. Following whole-body exposure to 27 mJ/cm2 of UVB, there was a significant racial group effect on serum vitamin D3 levels. Post-UVB levels were significantly higher in whites (31.4 +/- 4.4 nmol/L) than in Indians or blacks (12.8 +/- 2.9 and 9.1 +/- 2.1 nmol/L, respectively), while the levels in Orientals (27.8 +/- 4.4 nmol/L) differed significantly from those in blacks and Indians but not in whites. Race had only a marginal effect on serum 25-hydroxyvitamin D, with higher levels in whites than in blacks (69.9 +/- 12.7 vs 29.7 +/- 6.2 nmol/L). Serum 1,25-dihydroxyvitamin D and vitamin D binding protein levels were similar in all groups. We conclude that while racial pigmentation has a photoprotective effect, it does not prevent the generation of normal levels of active vitamin D metabolites.
导致种族色素沉着的表皮黑色素含量各异，这决定了到达较低（马尔皮基氏）细胞层的光子数量，而维生素D3的合成就在该细胞层进行。我们研究了种族色素沉着对维生素D3形成的影响，用固定剂量的UVB辐射（波长290至320纳米）刺激这一过程。通过测量血清25-羟基维生素D和最具活性的血清代谢物1,25-二羟基维生素D，进一步评估维生素D的营养状况。实验对象为年轻（三十岁左右）且健康的白人、东方人（东亚人）、印度人（南亚人）和黑人。各组的基础血清维生素D3水平相似，黑人的水平为2.3±0.6纳摩尔/升（平均值±标准误），印度人为3.4±1.0纳摩尔/升。全身暴露于27毫焦/平方厘米的UVB后，血清维生素D3水平存在显著的种族群体效应。UVB照射后，白人的水平（31.4±4.4纳摩尔/升）显著高于印度人或黑人（分别为12.8±2.9和9.1±2.1纳摩尔/升），而东方人（27.8±4.4纳摩尔/升）的水平与黑人和印度人有显著差异，但与白人无显著差异。种族对血清25-羟基维生素D仅有轻微影响，白人的水平高于黑人（69.9±12.7对29.7±6.2纳摩尔/升）。所有组的血清1,25-二羟基维生素D和维生素D结合蛋白水平相似。我们得出结论，虽然种族色素沉着具有光保护作用，但它并不能阻止活性维生素D代谢物正常水平的生成。
