Effect of dietary calcium on bone metabolism in young and aged female rats using a short-term in vivo model

Journal Article · Sat Oct 01 04:00:00 EDT 1988 · J. Nutr.; (United States)

OSTI ID:6868118

Sinha, R; Smith, Jr, J C; Soares, Jr, J H

The use of high dietary calcium supplementation in the treatment of patients with osteoporosis is controversial. The present study examined the mechanisms underlying the effects of calcium supplementation by investigating the influence of dietary calcium on bone dynamics in young and aged rats. A 2 x 2 x 2 factorial design was utilized with 0.2% (low) or 1.0% (high) calcium, 2- or 24-m-old female Long-Evans rats that were implanted subcutaneously with demineralized (DB) and mineralized (MB) bone powder. The four groups of rats were fed each of the respective diets for 11 wk and then implanted with one number5 gelatin capsule containing 30 mg of DB and another containing 100 mg of MB powder. The animals were injected intraperitoneally with 0.1 microCi/g body weight with 45Ca 14 h before the end of experiment. The ectopic bone as well as the right femurs were harvested 14 d after the rats were implanted. Marker enzyme activities (alkaline-formation and acid-resorption phosphatase), 45Ca uptake and calcium content were measured in the implants and the distal epiphyses of the right femurs. Bone turnover was higher in the young rats than in the old animals, and high dietary calcium in the young animals increased bone formation, as indicated by alkaline phosphatase activity. Dietary calcium level did not affect ectopic bone formation or resorption in the aged rats. The results indicate that high dietary intake of calcium does not affect bone dynamics in aged female rats but does increase bone formation in young rats.

• Research Organization: Univ. of Maryland, College Park (USA)
• OSTI ID: 6868118
• Journal Information: J. Nutr.; (United States), Journal Name: J. Nutr.; (United States) Vol. 118:10; ISSN JONUA
• Country of Publication: United States
• Language: English

Related Subjects

550501* -- Metabolism-- Tracer Techniques
550901 -- Pathology-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ACID PHOSPHATASE
AGE DEPENDENCE
ALKALINE EARTH ISOTOPES
ALKALINE EARTH METALS
ALKALINE PHOSPHATASE
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOLOGICAL MODELS
BODY
CALCIUM
CALCIUM 45
CALCIUM ISOTOPES
DAYS LIVING RADIOISOTOPES
DIET
DISEASES
ELEMENTS
ENZYME ACTIVITY
ENZYMES
ESTERASES
EVEN-ODD NUCLEI
HYDROLASES
INTERMEDIATE MASS NUCLEI
ISOTOPE APPLICATIONS
ISOTOPES
MAMMALS
METABOLISM
METALS
NUCLEI
ORGANS
OSTEOPOROSIS
PATHOGENESIS
PHOSPHATASES
RADIOISOTOPES
RATS
RODENTS
SKELETAL DISEASES
SKELETON
TRACER TECHNIQUES
UPTAKE
VERTEBRATES