title: Comparative effects of vitamin K and vitamin D supplementation on calcium balance in young rats fed normal or low calcium diets.
abstract: We examined the effect of vitamin K and vitamin D supplementation on calcium balance in young rats fed a normal or low calcium diet. Eighty female Sprague-Dawley rats, 6 wk of age, were randomized by the stratified weight method into eight groups with 10 rats in each group: 0.5% (normal) or 0.1% (low) calcium diet, 0.5% or 0.1% calcium diet+vitamin K (vitamin K2, menatetrenone, 30 mg/100 g, food intake), 0.5% or 0.1% calcium diet+vitamin D (25 microg/100 g, food intake), and 0.5% or 0.1% calcium diet+vitamin K+vitamin D. The duration of the study was 10 wk. Vitamin K supplementation promoted the reduction in urinary calcium excretion and retarded the abnormal elevation of serum PTH level in rats fed a low calcium diet, and stimulated intestinal calcium absorption in rats fed a normal calcium diet. Vitamin D supplementation stimulated intestinal calcium absorption with prevention of the abnormal elevation of serum PTH levels and prevented hypocalcemia in rats fed a low calcium diet, and stimulated intestinal calcium absorption in rats fed a normal calcium diet. The stimulation of intestinal calcium absorption was associated with increased serum 1,25-dihydroxyvitamin D levels. An additive effect of vitamin K and vitamin D on intestinal calcium absorption was found only in rats fed a normal calcium diet. This study shows the differential effects of vitamin K and vitamin D supplementation on calcium balance in young rats fed a normal or low calcium diet.
authors.affiliation: Department of Sports Medicine, Keio University School of Medicine, Shinjuku-ku, Tokyo, Japan. jiwamoto@sc.itc.keio.ac.jp
authors.forename: Jun
authors.initials: J
authors.lastname: Iwamoto
authors.forename: James K
authors.initials: JK
authors.lastname: Yeh
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Takeda
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Sato
mesh_terms: D000818:Animals; D002117:Calcitriol / Q000097:blood; D002118:Calcium / Q000097:blood / Q000378:metabolism* / Q000652:urine; D002136:Calcium, Dietary / Q000008:administration & dosage* / Q000493:pharmacokinetics; D019587:Dietary Supplements; D004347:Drug Interactions; D005260:Female; D006706:Homeostasis / Q000187:drug effects; D006996:Hypocalcemia / Q000517:prevention & control; D007408:Intestinal Absorption / Q000187:drug effects; D010281:Parathyroid Hormone / Q000097:blood; D010758:Phosphorus / Q000097:blood; D051381:Rats; D017207:Rats, Sprague-Dawley; D014807:Vitamin D / Q000008:administration & dosage*; D014812:Vitamin K / Q000008:administration & dosage*
chemical_list: D002136:Calcium, Dietary; D010281:Parathyroid Hormone; D014812:Vitamin K; D014807:Vitamin D; D010758:Phosphorus; D002117:Calcitriol; D002118:Calcium