Zinc enhancement of 17beta-estradiol's anabolic effect in osteoblastic MC3T3-E1 cells.
The anabolic effect of 17beta-estradiol in osteoblastic MC3T3-E1 cells was investigated. The cells were cultured for 3 days in the medium containing either vehicle or 17beta-estradiol (10(-11)-10(-9) M). 17beta-Estradiol significantly increased alkaline phosphatase activity and protein concentration in the cells. The steroid (10(-9) M) also significantly elevated the cell numbers and the cellular DNA content. The anabolic effect by 17beta-estradiol was blocked by the presence of dipicolinate (10(-3) M), a chelator of zinc ion, suggesting a role of cellular zinc in osteoblastic cell function. The presence of zinc sulfate (10(-5) M) or beta-alanyl-L-histidinato zinc (AHZ) (10(-5) M) significantly enhanced the 17beta-estradiol (10(-10) or 10(-9) M)-induced increase of alkaline phosphatase activity and protein concentration in the cells; the effect of AHZ was greater than that of zinc sulfate. The enhancement by zinc compounds was not based on the augmentation of osteoblastic cell numbers. The co-addition of cycloheximide (10(-6) M), an inhibitor of protein synthesis, completely blocked the zinc compound (10(-5) M)-induced enhancement of 17beta-estradiol's (10(-9) M) effect to increase alkaline phosphatase activity and protein concentration in the cells. Moreover, the anabolic effect of 17beta-estradiol together with or without zinc compounds was abolished by the presence of staurosporine (10(-8) M), an inhibitor of protein kinase C, or of okadaic acid (10(-7) M), an inhibitor of protein phosphatase. The present study demonstrates that the anabolic effect of 17beta-estradiol is enhanced by zinc-chelating dipeptide in osteoblastic MC3T3-E1 cells, and that the enhancing effect may involve protein synthesis and protein kinase activity.
Yamaguchi
M
M
Laboratory of Endocrinology and Molecular Metabolism, Graduate School of Nutritional Sciences, University of Shizuoka, 52-1 Yada, Shizuoka City 422, Japan.
Matsui
T
T
D016475:3T3 Cells; D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D002336:Carnosine / Q000031:analogs & derivatives* / Q000494:pharmacology; D002452:Cell Count; D002478:Cells, Cultured; D003513:Cycloheximide / Q000633:toxicity; D004247:DNA / Q000378:metabolism; D004357:Drug Synergism; D004791:Enzyme Inhibitors / Q000633:toxicity; D004958:Estradiol / Q000494:pharmacology*; D007502:Iron Chelating Agents / Q000633:toxicity; D051379:Mice; D019319:Okadaic Acid / Q000633:toxicity; D009942:Organometallic Compounds / Q000494:pharmacology*; D010006:Osteoblasts / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D010848:Picolinic Acids / Q000633:toxicity; D047428:Protein Kinase Inhibitors; D011500:Protein Synthesis Inhibitors / Q000633:toxicity; D011506:Proteins / Q000378:metabolism; D019311:Staurosporine / Q000633:toxicity; D015032:Zinc / Q000378:metabolism*; D017967:Zinc Compounds; D019287:Zinc Sulfate / Q000494:pharmacology*
D004791:Enzyme Inhibitors; D007502:Iron Chelating Agents; D009942:Organometallic Compounds; D010848:Picolinic Acids; D047428:Protein Kinase Inhibitors; D011500:Protein Synthesis Inhibitors; D011506:Proteins; D017967:Zinc Compounds; C061957:polaprezinc; D019319:Okadaic Acid; D004958:Estradiol; D019287:Zinc Sulfate; D002336:Carnosine; D004247:DNA; D003513:Cycloheximide; D000469:Alkaline Phosphatase; D019311:Staurosporine; D015032:Zinc; C030614:picolinic acid