Mechanism of mobilization of bone mineral by 1,25-dihydroxyvitamin D/sub 3/

Journal Article · Mon Jan 01 04:00:00 EST 1979 · Am. J. Physiol.; (United States)

OSTI ID:6868853

Brommage, R; Neuman, W F

To better understand the mechanism(s) by which 1,25-dihydroxyvitamin D/sub 3/(1,25(OH)/sub 2/D/sub 3/ promotes the mobilization of bone mineral, calvarial lactate production, and mineral solubility were studied in an in vitro incubation system. The calvairae were obtained from neonatal mice, some of which were previously injected with 20 ng of 1,25(OH)/sub 2/D/sub 3/. In live bones 1,25(OH)/sub 2/D/sub 3/ mobilized bone mineral as evidenced by the increased release of both calcium and phosphate into the medium throughout 48 h of incubation. When examined as a function of incubation time and the interval between injection and incubation, 1,25(OH)/sub 2/D/sub 3/ did not affect lactate production. Apparently, 1,25(OH)/sub 2/D/sub 3/ does not mobilize skeletal mineral through a lactate-mediated pH gradient mechanism. Over 4 days of incubation, 1,25(OH)/sub 2/D/sub 3/-treated calvariae supported higher buffer levels of calcium and phosphate in the absence of cellular metabolism, indicating the solubility of bone mineral was increased by 1,25(OH)/sub 2/D/sub 3/ treatment. Because the effects of 1,25(OH)/sub 2/D/sub 3/ were observed in nonvital bone, a pump mechanism cannot fully explain the 1,25(OH)/sub 2/D/sub 3/-induced transfer of calcium and phosphate from bone to blood. These findings suggest that a mechanism involving an increase in bone mineral solubility, presumably mediated through a mineral solubilizer(s), is at least partially responsible for the skeletal actions of 1,25(OH)/sub 2/D/sub 3/.

• Research Organization: Univ. of Rochester, NY
• OSTI ID: 6868853
• Journal Information: Am. J. Physiol.; (United States), Journal Name: Am. J. Physiol.; (United States) Vol. 237:2; ISSN AJPHA
• Country of Publication: United States
• Language: English

Related Subjects

550200* -- Biochemistry
551000 -- Physiological Systems
59 BASIC BIOLOGICAL SCIENCES
ALKALINE EARTH METALS
ANIMALS
BIOLOGICAL EFFECTS
BIOLOGICAL PATHWAYS
BODY
CALCIUM
CHOLECALCIFEROL
ELEMENTS
ENZYMES
HEMIACETAL DEHYDROGENASES
IN VITRO
LACTATE DEHYDROGENASE
MAMMALS
METABOLISM
METALS
MICE
ORGANS
OXIDOREDUCTASES
OXYGEN COMPOUNDS
PH VALUE
PHOSPHATES
PHOSPHORUS COMPOUNDS
PHYSIOLOGY
RODENTS
SKELETON
SOLUBILITY
VERTEBRATES
VITAMIN D
VITAMINS