Effects of 7-isopropoxy-3-phenyl-4H-1-benzopyran-4-one (ipriflavone) on serum levels of calcitonin and parathyroid hormone in patients with adult-onset diabetes

Abstract

The effects of 1α-hydroxycholecalciferol [1α(OH)D3] and 7-isopropoxy-3-phenyl-4H-1-benzopyran-4-one [ipriflavone (IP)] on the serum concentrations of parathyroid hormone (PTH) and calcitonin (CTN) were studied in patients with adult-onset diabetes (NIDDM). A group of 122 NIDDM patients with unrestricted caloric intake were divided by random sampling into dietary (D) and non-dietary (ND) groups. Group D was placed on a calorie-restricted diet while group ND remained free of dietary restrictions. Two years after the groups were so divided, the groups were further divided by random sampling into 2 sub-groups (D1 and D2; ND1 and ND2). Groups D1 and ND1 received 1α(OH)D3 for 2 months, followed by combined IP/1α(OH)D3 administration for 6 months, and groups D2 and ND2 received a placebo in place of 1α(OH)D3. Serum PTH levels were higher and serum CTN levels were lower in group D than in group ND. Administration of 1α(OH)D3 to group D1 patients decreased serum PTH levels and increased serum calcium concentration, although serum CTN levels were not affected. Serum CTN levels were found to increase significantly (p<0.01), without changes in serum PTH concentrations, during the 6 months, combination treatment of 1α(OH)D3 and IP. IP also increased CTN levels in group ND2 and in patients in group D2 who had no prior 1α(OH)D3 treatment. IP did not, however, increase serum CTN levels significantly in patients whose serum PTH concentration was relatively high (500 pg/ml or more). These results suggest that IP is suitable for increasing serum CTN levels in NIDDM patients, and that its action is dependent on serum PTH levels.