Active forms of vitamin D3, 1 alpha-hydroxyvitamin D3 and 1 alpha,25-dihydroxyvitamin D3, were administered in an open-design study to 40 patients with psoriasis vulgaris in three ways: to 17 patients 1 alpha-hydroxyvitamin D3 was given orally at a dose of 1.0 micrograms/day for 6 months, to four patients 1 alpha,25-dihydroxyvitamin D3 was given orally at a dose of 0.5 microgram/day for 6 months, and 19 patients were given 1 alpha,25-dihydroxyvitamin D3 applied topically at concentration of 0.5 microgram/g of base for 8 weeks. Improvement was observed at the end of the individual study periods in 13 (76%) patients in Group 1 with a mean period of treatment (+/- SD) of 2.7 +/- 0.6 months, in one patient in Group 2 at 3 months after the start of treatment, and in 16 (84%) patients in Group 3 when the chemical was applied for 3.3 +/- 1.2 weeks. No side-effects were observed in any of these trials. These data suggest that psoriasis may respond to active metabolites of vitamin D3 and that abnormalities in vitamin D metabolism or in responsiveness of the skin cells to active metabolites of vitamin D may be involved in the pathogenesis of this skin disease.

Patients with acromegaly have alterations in mineral metabolism. To determine the effect of correction of excess GH secretion on calcium metabolism, we studied 12 acromegalic patients before and 3-4 weeks after pituitary adenomectomy. Treatment of acromegaly resulted in significant decreases in both serum calcium [from 9.3 +/- 0.2 to 8.7 +/- 0.1 mg/dl (mean +/- SEM); P less than 0.01] and urinary calcium excretion (from 200 +/- 24 to 88 +/- 12 mg/24 h; P less than 0.0002). Serum phosphate also decreased significantly (P less than 0.01) from 4.8 +/- 0.2 to 4.3 +/- 0.2 mg/dl. Both serum immunoreactive PTH and calcitonin levels were normal initially and did not change after surgery. The mean serum 25-hydroxyvitamin D (25OHD) level was significantly (P less than 0.01) lower and the 1,25-dihydroxyvitamin D [1,25-(OH)2D] level was significantly (P less than 0.0001) higher in acromegaly compared with measurements in 25 normal subjects. After surgery, the serum 25OHD level did not change; however, the serum 1,25-(OH)2D concentration fell significantly (P less than 0.0001) from 60 +/- 4 to 43 +/- 2 pg/ml. A positive correlation was found between the decrements in urinary calcium excretion and the serum 1,25-(OH)2D level when the comparison was made between the decrements as percentages of pretreatment values (r = 0.64; P less than 0.05). The accumulated data suggest that the hypercalciuria in acromegaly might be due to intestinal calcium hyperabsorption, which could be attributed to the elevated circulating 1,25-(OH)2D level. Excessive GH secretion might stimulate the production of 1,25-(OH)2D and might also directly stimulate calcium absorption.

The effects of topical administration of 1,25-dihydroxyvitamin D3, as 0.1 and 0.5 microgram per g base, and control base applied to contralateral skin lesions in five patients with persistent psoriasis were compared. In all five, definite and in some cases remarkable improvement of the lesions was seen when 1,25-dihydroxyvitamin D3 at concentration of 0.5 microgram per g base was applied for two to five weeks. No local or systemic toxicity was detected in any patient. Although the mechanism of the improvement is yet to be elucidated, these results show the possible effectiveness of topical 1,25-dihydroxyvitamin D3 on psoriatic skin lesions.

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