Influence of ultraviolet irradiation on plasma vitamin D and calcitonin levels in humans.

In 13 patients with essential hypertension (EH) and in 10 normotensive controls, the influence of ultraviolet irradiation on plasma calcium, phosphorus, 25-OH-D, 1,25(OH)2D and calcitonin (CT) was studied. The basal levels of total calcium (2.47 +/- 0.02 mmol/liter) and phosphorus (1.10 +/- 0.04 mmol/liter) in patients with essential hypertension were not different from the control subjects (2.49 +/- 0.05 mmol/liter and 1.22 +/- 0.06 mmol/liter, respectively). However, patients with essential hypertension had elevated levels of 25-OH-D (68.09 +/- 7.48 vs. 26.51 +/- 3.3 mg/ml), 1,25(OH)2D (175.15 +/- 32.5 pmol/liter vs. 118.0 +/- 13.23 pmol/liter) and CT (131.7 +/- 32.36 pg/ml vs. 49.0 +/- 18.62 pg/ml) than in control subjects. In contrast to normotensive subjects, the majority of hypertensive patients showed no rise of plasma 25-OH-D and 1,25(OH)2D in response to ultraviolet irradiation. The results of this study suggest involvement of abnormal vitamin D metabolism in the pathogenesis of hypertension, at least in some patients.