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.

We evaluated the bone mineral density (BMD) of the bilateral femurs in 112 patients with hemiplegia using dual-energy X-ray absorptiometry in order to elucidate the effect of disuse and immobilization. BMD of the paretic side was significantly reduced compared with that of the non-paretic side in hemiplegic patients (femoral neck 0.582 +/- 0.014 g/cm2 versus 0.623 +/- 0.014 g/cm2 and total femur 0.645 +/- 0.02 g/cm2 versus 0.702 +/- 0.017 g/cm2; mean +/- SEM, P < 0.01, respectively). Femoral BMD in both the paretic and nonparetic limb had significantly (P < 0.01) lower values than in age- and sex-matched controls, but the paretic side had a more significant reduction of BMD; femoral neck -20% versus -14% and total femur -24% versus -18%. In addition, patients with impaired activities of daily living (ADL), evaluated by a mobility score, had significantly decreased BMD ratios of paretic/nonparetic side than patients with improved ADL (femoral neck 91% versus 97%, P < 0.01 and total femur 89% versus 94%, P < 0.05). Our results indicated that BMD of both femurs of patients with hemiplegia was reduced, although the paretic side showed a greater BMD decrease. This decrease might be prevented or reduced by improvement of ADL.

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