EFFECTS OF INTRAVENOUS CALCITRIOL ON LIPID PROFILES AND GLUCOSE-TOLERANCE IN UREMIC PATIENTS WITH SECONDARY HYPERPARATHYROIDISM

1. Secondary hyperparathyroidism in chronic renal failure may contribu te to abnormalities of lipid metabolism and glucose tolerance. Amelior ation of secondary hyperparathyroidism has been reported to mitigate t he hyperlipidaemia and improve glucose tolerance experimentally. 2. Th e effect of the partial suppression of hyperparathyroidism by intraven ous calcitriol on lipid levels and glucose tolerance was studied in 15 haemodialysis patients with secondary hyperparathyroidism. All receiv ed intravenous calcitriol 1 mu g at the end of haemodialysis thrice we ekly for eight weeks. Oral glucose tolerance test and plasma lipid pro files including triglyceride, total cholesterol, high density lipoprot ein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), apoprotein A-I and apoprotein B were determined simultaneously before and after eight weeks of therapy. 3. Before calcitriol treatment, urae mic patients with secondary hyperparathyroidism displayed a significan t higher triglyceride and a significant lower HDL-C and apoprotein A-I as well as marked glucose intolerance with an increment of the area b elow the glucose curve when compared with healthy control subjects. 4. After eight weeks of calcitriol treatment, there was a significant de crement in serum intact parathyroid hormone (476.45 +/- 48.33 versus 1 91.37 +/- 30.17 ng/l, P < 0.001) and plasma triglyceride (2.24 +/- 0.3 4 versus 1.80 +/- 0.29 mmol/l, P < 0.05) as well as a significant incr ement of plasma apoprotein A-I (38.13 +/- 2.14 versus 44.19 +/- 2.18 m u mol/l, P < 0.05), whereas there was no significant change in serum t otal cholesterol, LDL-C, HDL-C, and apoprotein B. These patients also became more glucose tolerant with a significant decrease of the area b elow the glucose curve and a significant rise in the area under the in sulin curve after glucose load. Furthermore, the insulinogenic index i ncreased significantly. 5. It was concluded that in addition to 1,25-d ihydroxyvitamin D-3 deficiency, secondary hyperparathyroidism may part icipate in the abnormal lipid metabolism, glucose tolerance and insuli n secretion seen in dialysis patients and these abnormalities could be , at least in part, improved by intravenous calcitriol treatment.