title: Alternation in bone components with increasing age of newborn rats: role of zinc in bone growth.
abstract: The effect of zinc on bone growth in newborn rats supplied with lactation by maternal rats was investigated. Newborn rats were killed between 1 and 35 days after birth. Increasing age caused a significant increase in zinc content, calcium content, and alkaline phosphatase activity in the femoral-diaphyseal and metaphyseal tissues, while the bone deoxyribonucleic acid (DNA) content was significantly decreased because of elevation of mineral content. Oral administration of zinc sulfate (2.0mg/100g body weight; four times at 24-h intervals) to maternal rats from 1 day after birth induced a significant increase in zinc, alkaline phosphatase activity, DNA, and calcium content in the femoral-diaphyseal and metaphyseal tissues of newborn rats compared with those 7 or 14 days old. The results indicate that the increase in bone components results from lactation with zinc-containing milk of maternal rats. The femoral-metaphyseal tissues of newborn rats obtained at 7 days after birth were cultured for 24h in a medium containing either vehicle or zinc sulfate (10(-6) to 10(-4) M) in vitro. Bone alkaline phosphatase activity and calcium and DNA content were significantly increased by zinc addition. These increases were completely prevented by the presence of dipicolinate (10(-3) M), a chelator of zinc ion, or cycloheximide (10(-6) M), an inhibitor of protein synthesis. The present study suggests that zinc plays a role in the development of bone growth in newborn rats.
authors.affiliation: Laboratory of Endocrinology and Molecular Metabolism, Graduate School of Nutritional Sciences, University of Shizuoka, Yada, Japan.
authors.forename: Z J
authors.initials: ZJ
authors.lastname: Ma
authors.forename: M
authors.initials: M
authors.lastname: Yamaguchi
mesh_terms: D000375:Aging / Q000378:metabolism / Q000502:physiology*; D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D000831:Animals, Newborn; D001846:Bone Development / Q000502:physiology*; D002118:Calcium / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D005260:Female; D005269:Femur / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D007774:Lactation; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D015032:Zinc / Q000378:metabolism / Q000502:physiology*; D019287:Zinc Sulfate / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology
chemical_list: D019287:Zinc Sulfate; D004247:DNA; D000469:Alkaline Phosphatase; D015032:Zinc; D002118:Calcium