Calcitriol corrects deficient calcitonin secretion in the vitamin D-deficient elderly.
The thyroid calcitonin-producing C cells possess vitamin D receptors and synthesize the vitamin D-dependent calbindin D28K. The present study evaluates the possible direct or indirect influence of vitamin D on calcitonin secretion in the elderly. Serum calcitonin was measured before and after a short calcium infusion (1.5 mg/kg over 10 minutes) in nine normal young adults (30 +/- 4 years, mean +/- SEM) and eight elderly subjects (78 +/- 4 years). The test was repeated 48 h after the last of three intravenous injections of calcitriol (2 micrograms) given every other day. Basal serum calcium did not change, but basal calcitonin of the elderly increased from 7 +/- 1 to 10 +/- 1 pg/ml (p < 0.06), similar to basal values in young adults (11 +/- 1 pg/ml). The increase in calcitonin after calcium infusion increased from 8 +/- 1 to 14 +/- 1 pg/ml (p < 0.001) after calcitriol treatment and approached the increase in young adults (18 +/- 3 pg/ml). These data demonstrate that calcitriol can improve and nearly normalize the impaired calcitonin secretion of the mildly vitamin D-deficient elderly subjects without changes in serum calcium, whereas the inverse situation is observed for parathyroid hormone.
Quesada
J M
JM
Unidad Metabolismo Mineral, Hospital Reina Sofia, Cordoba, Spain.
Mateo
A
A
Jans
I
I
Rodriguez
M
M
Bouillon
R
R
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D001842:Bone and Bones / Q000187:drug effects / Q000378:metabolism; D002116:Calcitonin / Q000097:blood / Q000378:metabolism*; D002117:Calcitriol / Q000008:administration & dosage / Q000494:pharmacology* / Q000627:therapeutic use; D002118:Calcium / Q000097:blood; D005260:Female; D006801:Humans; D007275:Injections, Intravenous; D008297:Male; D014808:Vitamin D Deficiency / Q000188:drug therapy / Q000378:metabolism*
D015415:Biomarkers; D002116:Calcitonin; D002117:Calcitriol; D002118:Calcium