Zinc enhancement of 17beta-estradiol's anabolic effect in osteoblastic MC3T3-E1 cells

Calcif Tissue Int. 1997 Jun;60(6):527-32.

Abstract

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.

MeSH terms

  • 3T3 Cells
  • Alkaline Phosphatase / metabolism
  • Animals
  • Carnosine / analogs & derivatives*
  • Carnosine / pharmacology
  • Cell Count
  • Cells, Cultured
  • Cycloheximide / toxicity
  • DNA / metabolism
  • Drug Synergism
  • Enzyme Inhibitors / toxicity
  • Estradiol / pharmacology*
  • Iron Chelating Agents / toxicity
  • Mice
  • Okadaic Acid / toxicity
  • Organometallic Compounds / pharmacology*
  • Osteoblasts / cytology
  • Osteoblasts / drug effects*
  • Osteoblasts / enzymology
  • Osteoblasts / metabolism
  • Picolinic Acids / toxicity
  • Protein Kinase Inhibitors
  • Protein Synthesis Inhibitors / toxicity
  • Proteins / metabolism
  • Staurosporine / toxicity
  • Zinc / metabolism*
  • Zinc Compounds
  • Zinc Sulfate / pharmacology*

Substances

  • Enzyme Inhibitors
  • Iron Chelating Agents
  • Organometallic Compounds
  • Picolinic Acids
  • Protein Kinase Inhibitors
  • Protein Synthesis Inhibitors
  • Proteins
  • Zinc Compounds
  • polaprezinc
  • Okadaic Acid
  • Estradiol
  • Zinc Sulfate
  • Carnosine
  • DNA
  • Cycloheximide
  • Alkaline Phosphatase
  • Staurosporine
  • Zinc
  • picolinic acid