beta-Cryptoxanthin stimulates bone formation and inhibits bone resorption in tissue culture in vitro.
The effect of beta-cryptoxanthin, which is greatly present in fruits, has not been clarified so far on bone metabolism. The effect of beta-cryptoxanthin on bone formation and bone resorption was investigated in tissue culture in vitro. Rat femoral-diaphyseal (cortical bone) and -metaphyseal (trabecular bone) tissues were cultured for 48 h in Dulbecco's modified Eagle's medium (high glucose, 4.5%) supplemented with antibiotics and bovine serum albumin. The experimental cultures contained 10(-8)-10(-5) M beta-cryptoxanthin. The presence of beta-cryptoxanthin (10(-6) or 10(-5) M) caused a significant increase in calcium content, alkaline phosphatase activity and deoxyribonucleic acid (DNA) content in the diaphyseal and metaphyseal tissues. These increases were completely prevented in the presence of cycloheximide (10(-6) M), an inhibitor of protein synthesis. beta-Carotene (10(-6) or 10(-5) M) or xantine (10(-6) or 10(-5) M) had no effect on the diaphyseal and metaphyseal calcium contents. The bone-resorbing factors parathyroid hormone (1-34) (PTH; 10(-7) M) or prostaglandin E2 (PGE2; 10(-5) M) caused a significant decrease in calcium content in the diaphyseal and metaphyseal tissues. The decrease in bone calcium content induced by PTH or PGE2 was completely inhibited by beta-cryptoxanthin (10(-8)-10(-6) M). In addition, beta-cryptoxanthin (10(-8)-10(-6) M) completely inhibited the PTH (10(-7) M)- or PGE, (10(-5) M)-induced increase in medium glucose consumption and lactic acid production by diaphyseal and metaphyseal tissues. The inhibitory effect of beta-cryptoxanthin (10(-7) M) on PTH (10(-7) M)- or PGE2 (10(-5) M)-stimulated decrease in the diaphyseal calcium content was significantly prevented in the presence of 10(-3) M vanadate, an inhibitor of protein tyrosine phosphatase. Vanadate (10(-3) M) did not have a significant effect on calcium content and lactic acid production in control bone tissues. The present study demonstrates that beta-cryptoxanthin has a direct stimulatory effect on bone formation and an inhibitory effect on bone resorption in tissue culture in vitro.
Yamaguchi
Masayoshi
M
Laboratory of Endocrinology and Molecular Metabolism, Graduate School of Nutritional Sciences, University of Shizuoka, Yada, Shizuoka, Japan. yamaguch@u-shizuoka-ken.ac.jp
Uchiyama
Satoshi
S
D000469:Alkaline Phosphatase / Q000096:biosynthesis; D000818:Animals; D016588:Anticarcinogenic Agents / Q000493:pharmacokinetics*; D001862:Bone Resorption / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D065366:Cryptoxanthins; D046508:Culture Techniques; D003513:Cycloheximide / Q000494:pharmacology; D004247:DNA / Q000096:biosynthesis; D015232:Dinoprostone / Q000494:pharmacology; D005269:Femur / Q000166:cytology / Q000378:metabolism; D005947:Glucose / Q000378:metabolism; D019344:Lactic Acid / Q000378:metabolism; D008297:Male; D010012:Osteogenesis / Q000187:drug effects / Q000502:physiology; D010281:Parathyroid Hormone / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D014638:Vanadates / Q000494:pharmacology; D024341:Xanthophylls; D019207:beta Carotene / Q000031:analogs & derivatives* / Q000494:pharmacology*
D016588:Anticarcinogenic Agents; D065366:Cryptoxanthins; D010281:Parathyroid Hormone; D024341:Xanthophylls; D019207:beta Carotene; D019344:Lactic Acid; D014638:Vanadates; D004247:DNA; D003513:Cycloheximide; D000469:Alkaline Phosphatase; D005947:Glucose; D015232:Dinoprostone; D002118:Calcium