The noncalcemic analogue of vitamin D, 22-oxacalcitriol, suppresses parathyroid hormone synthesis and secretion.
OCT, a non-calcemic analogue of 1,25(OH)2D3 has been found to have a more potent activity than that of 1,25(OH)2D3 regarding cell differentiation and immunopotentiation activity, and to prolong the average life span of MRL/l mice. Recently, we found that OCT effectively suppressed the secretion and synthesis of PTH without inducing hypercalcemia. In primary cultures of bovine parathyroid cells, OCT was capable of suppressing PTH release in a dose-dependent manner. OCT was also active in vivo, and, like 1,25(OH)2D3, decreased the pre-pro(PTH) mRNA levels. In a group of rats with CRF, daily administration of OCT, 8 ng i.p. for 2 weeks returned PTH levels to normal without changes in serum calcium. Preliminary results in dogs with CRF indicated that after the administration of OCT 5 micrograms i.v., N-terminal PTH decreased by 76% without changes in Ca. In conclusion, OCT may provide a unique contribution to the treatment of secondary hyperparathyroidism.
Nishii
Y
Y
Research Laboratory of Chugai Pharmaceutical Co., Tokyo, Japan.
Abe
J
J
Mori
T
T
Brown
A J
AJ
Dusso
A S
AS
Finch
J
J
Lopez-Hilker
S
S
Morrissey
J
J
Slatopolsky
E
E
D000818:Animals; D002117:Calcitriol / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology; D002478:Cells, Cultured; D006801:Humans; D010281:Parathyroid Hormone / Q000096:biosynthesis* / Q000378:metabolism
D010281:Parathyroid Hormone; D002117:Calcitriol; C051883:maxacalcitol