Response of alkaline phosphatase to zinc repletion in hypozincemic hemodialysis patients.
The response of serum alkaline phosphatase (AP), a zinc-dependent metalloenzyme, to zinc administration via the dialysate (400 micrograms/l) was examined in 14 hypozincemic (less than 30th percentile of dialysis patients) hemodialysis patients and in 14 placebo-treated matched dialysis control patients. Plasma zinc and serum AP were measured three times: prior to, once weekly during (5 weeks), and 2 weeks after addition of zinc to the dialysate. The serum zinc levels remained stable in placebo-treated controls (initial 87.7 +/- 12.5; final 78.6 +/- 8.3 micrograms/dl) and increased in zinc-treated patients (initial 76.4 +/- 8.3; 5th week 96.9 +/- 13.3; 2 weeks after zinc withdrawal 82.3 +/- 12.2 micrograms/dl). There was a slight increase of AP with time in placebo controls (initial 90.2 +/- 26.5; 5th week 100 +/- 29 U/l) and a more pronounced increase in zinc-treated patients (initial 90.8 +/- 19.9; 5th week 113 +/- 20.9 U/l). The difference between the two groups was marginally significant (p less than 0.05; analysis of variance). It is concluded that zinc repletion via dialysate with documented increase of serum zinc levels in initially hypozincemic dialysis patients causes a reversible increase of serum AP. The result is compatible with some tissue zinc deficiency in hypozincemic dialysis patients.
D000328:Adult; D000469:Alkaline Phosphatase / Q000097:blood*; D002712:Chlorides; D002986:Clinical Trials as Topic; D005260:Female; D006801:Humans; D007676:Kidney Failure, Chronic / Q000097:blood / Q000201:enzymology / Q000628:therapy; D008297:Male; D008875:Middle Aged; D006435:Renal Dialysis / Q000009:adverse effects*; D015032:Zinc / Q000097:blood / Q000172:deficiency / Q000627:therapeutic use*; D017967:Zinc Compounds
D002712:Chlorides; D017967:Zinc Compounds; C016837:zinc chloride; D000469:Alkaline Phosphatase; D015032:Zinc