Hypocalcemic effect of 24R, 25-dihydroxyvitamin D3 in rats.
The physiological significance of 24R,25-dihydroxyvitamin D3 [24R,25 (OH)2D3] is still controversial. The effects of 24R,25-(OH)2D3 on serum calcium level were examined in rats. While 24R,25-(OH)2D3 had no effect on serum calcium level in normal rats, 200 micrograms/kg of 24R,25-(OH)2D3 showed significant hypocalcemic effect in rats pretreated with vitamin D3 (changes of serum calcium level compared with control group were 1.3 and 1.5 mg/dl at 24 and 36 hours respectively) and also showed a significant antagonistic effect against the action of 1 alpha,25-dihydroxyvitamin D3 (1 alpha,25(OH)2D3) in the thyroparathyroidectomized rats (changes of serum calcium compared with control group were 0.5 and 0.8 mg/dl at 12 and 24 hours respectively). It was concluded that the effect of 24R,25-(OH)2D3 on serum calcium differs from that of 1 alpha,25-(OH)2D3.
Maeda
Y
Y
Biomedical Research Laboratories, Kureha Chemical Industry, Tokyo, Japan.
Yamato
H
H
Katoh
T
T
Orimo
H
H
D015650:24,25-Dihydroxyvitamin D 3 / Q000494:pharmacology*; D000818:Animals; D002112:Calcifediol / Q000494:pharmacology*; D002118:Calcium / Q000097:blood*; D008297:Male; D016105:Parathyroidectomy; D051381:Rats; D011919:Rats, Inbred Strains; D013965:Thyroidectomy
D015650:24,25-Dihydroxyvitamin D 3; D002112:Calcifediol; D002118:Calcium