321 HEPATIC METABOLISM OF VITAMIN D IN CHRONIC RENAL FAILURE
SIR,-Brancaccio et al.’ suggested that the essential point in pathogenesis of renal osteodystrophy is defective hepatic
the
25-hydroxylation of vitamin D. We should like to report the results of an experiment which strongly contest this view. Eight patients with chronic renal failure (C.R.F.) with a mean creatinine clearance of 10 ml/min and seven healthy volunteers were studied. All subjects had normal serum levels of albumin, bilirubin, and aspartate transaminase and none were receiving anticonvulsants (or any other enzyme-inducing agent), or vitamin-D supplements. All subjects received an intramuscular injection of 600 000 i.u. of vitamin DZ in arachis oil on day zero after baseline assessment of 2S-0HD. Further estimations of 25-OHD were done on days 3, 6, 9, and 12. The results obtained are shown in the figure. There was no significant difference between c.R.. patients and controls with respect to baseline 25-OHD levels (15.8 and 19.2 ng/ml, respectively). However, the mean incremental rises obtained in 25-OHD levels in response to vitamin D injection were greater in c.R.F. patients than in controls-the differences at 6 and 12 days being significant (p
SIR,-Brancaccio et al.’ suggested that the essential point in pathogenesis of renal osteodystrophy is defective hepatic
the
25-hydroxylation of vitamin D. We should like to report the results of an experiment which strongly contest this view. Eight patients with chronic renal failure (C.R.F.) with a mean creatinine clearance of 10 ml/min and seven healthy volunteers were studied. All subjects had normal serum levels of albumin, bilirubin, and aspartate transaminase and none were receiving anticonvulsants (or any other enzyme-inducing agent), or vitamin-D supplements. All subjects received an intramuscular injection of 600 000 i.u. of vitamin DZ in arachis oil on day zero after baseline assessment of 2S-0HD. Further estimations of 25-OHD were done on days 3, 6, 9, and 12. The results obtained are shown in the figure. There was no significant difference between c.R.. patients and controls with respect to baseline 25-OHD levels (15.8 and 19.2 ng/ml, respectively). However, the mean incremental rises obtained in 25-OHD levels in response to vitamin D injection were greater in c.R.F. patients than in controls-the differences at 6 and 12 days being significant (p
