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.

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Lipid metabolism was studied in 16 acromegalic patients who all underwent transsphenoidal selective pituitary adenomectomy (SPA). Before the operation, their serum lipid levels correlated with none of the basal levels of serum growth hormone (GH), basal levels of plasma somatomedin-C (SM-C), fasting levels of plasma glucose (FPG), peak levels of plasma glucose (PGp) or basal and peak levels of serum immunoreactive insulin (IRIb and IRIp, resp.) in the oral glucose tolerance test (OGTT), and obesity indices. The serum GH levels as well as plasma SM-C levels in the group with decreased serum high density lipoprotein-cholesterol (HDL-C) differed greatly from those of the normal HDL-C group. However, there was no significant difference in either serum GH or plasma SM-C between groups with and without metabolic abnormality of any other lipid examined.After the operation, the basal levels of serum GH and plasma SM-C decreased significantly. In conjunction with these changes, PGp, serum IRIb, serum triglyceride (TG), non-esterified fatty acid (NEFA) and very low density lipoprotein (VLDL) decreased significantly. In contrast, serum HDL-C increased significantly. However, FPG, serum IRIp, obesity indices, serum total cholesterol (TC) and serum low density lipoprotein (LDL) showed no significant change.There were no significant differences in the levels of any serum lipid either before or after surgery among the diabetic, borderline and normal types defined by the preoperative OGTT patterns. Atherogenic indices (AIs) decreased significantly and returned to normal postoperatively.These results suggest that obesity or secondary diabetes is not a direct cause of hyperlipidemia in acromegaly.The prognosis of acromegaly is affected by arteriosclerotic complications.It is intriguing, therefore, that AIs were normalized by transsphenoidal SPA. Being rather a safe procedure, it can be performed without hesitation, aside from a conservative treatment. vascular Diseases,