Opposite effects of calcitriol and paricalcitol on the parathyroid hormone-(1-84)/large carboxy-terminal-parathyroid hormone fragments ratio in patients with stage 5 chronic kidney disease.
OBJECTIVE
The effects of calcitriol and paricalcitol on circulating levels of intact parathyroid hormone, parathyroid hormone-(1-84), the large carboxy-terminal-parathyroid hormone fragments, and the parathyroid hormone-(1-84)/carboxy-terminal-parathyroid hormone fragments were studied.


METHODS
In the longitudinal study, 31 hemodialysis patients who were receiving intravenous calcitriol or paricalcitol were followed for 6 to 8 wk. After a washout period, patients were treated with the other vitamin D compound for 6 to 8 wk. Plasma intact parathyroid hormone and parathyroid hormone-(1-84) were measured, and the parathyroid hormone ratio was calculated. In the cross-sectional study, results of intact parathyroid hormone, parathyroid hormone-(1-84), and parathyroid hormone ratio were compared between patients who were treated with paricalcitol (n = 49) versus no vitamin D therapy (n = 44).


RESULTS
In the longitudinal study, the parathyroid hormone ratio was significantly lower in patients who were treated with calcitriol and higher with paricalcitol treatment compared with values that were obtained during washout. In the cross-sectional study, intact parathyroid hormone levels were identical in both groups, whereas parathyroid hormone-(1-84) and thus parathyroid hormone ratio values were higher in patients who were given paricalcitol than in patients who were not receiving vitamin D.


CONCLUSIONS
These data show that at similar intact parathyroid hormone values, the active parathyroid hormone-(1-84) compound is lower with calcitriol than with paricalcitol treatment. This finding might be relevant for choice of vitamin D compound in patients with stage 5 chronic kidney disease.
Monier-Faugere
Marie-Claude
MC
Division of Nephrology, Bone and Mineral Metabolism, University of Kentucky, Lexington, KY 40536-0084, USA.
Mawad
Hanna
H
Malluche
Hartmut H
HH
D000328:Adult; D000368:Aged; D002117:Calcitriol; D002908:Chronic Disease; D003430:Cross-Sectional Studies; D004872:Ergocalciferols / Q000494:pharmacology*; D005260:Female; D006801:Humans; D006962:Hyperparathyroidism, Secondary / Q000097:blood / Q000188:drug therapy*; D007674:Kidney Diseases / Q000097:blood*; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood*; D010446:Peptide Fragments / Q000097:blood*; D006435:Renal Dialysis
D004872:Ergocalciferols; D010281:Parathyroid Hormone; D010446:Peptide Fragments; C084656:paricalcitol; D002117:Calcitriol