Possible Role of Tyrosine Kinases in the Prolactin Stimulation of Cell Division in Nb₂ Node Lymphoma Cells

Summary

Orthovanadate and genistein were employed to determine the possible role of tyrosine kinase in the prolactin stimulation of cell division in Nb₂ node lymphoma cells. Orthovanadate (0.1-0.25 μM), an inhibitor of specific phosphatases, was found to stimulate cell division as well as potentiate the mitogenic effect of prolactin on Nb₂ cells when prolactin was employed at a less than maximum stimulatory concentration. Genistein, an inhibitor of tyrosine kinase, was found to inhibit the prolactin stimulation of cell division. Since prolactin was shown in earlier studies to stimulate the phosphorylation of tyrosyl residues in specific Nb₂ cell proteins, these results suggest that the signal transduction pathway for the prolactin stimulation of cell division in the Nb₂ node lymphoma cells likely involves the participation of tyrosine kinase(s).

Key words

Genistein - Orthovanadate - Nb₂ Node Lymphoma Cells - Tyrosine Kinase - Tyrosine Phosphatase - Prolactin