Effect of the tyrosine kinase inhibitor tyrphostin on insulin binding and insulin imprinting of Tetrahymena.

After 10 min treatment with the tyrosine kinase inhibitor tyrphostin the fluorescein isothiocyanate (FITC)-insulin binding of Tetrahymena was increased. This binding characteristic was not changed when tyrphostin and insulin acted together. Consecutive treatments with 10 min tyrphostin and 10 min insulin further increased the FITC-insulin binding. Due to the effect of treatment with tyrphostin there was a decreased insulin binding in the offspring generations after 24 h. There was increased insulin binding in those cells of which the progenitor was treated not only by tyrphostin but also with insulin, but the insulin binding was still below the control level in this group. The increase of binding in the offspring generations of cells which were treated consecutively by tyrphostin and insulin compared with cells treated with only tyrphostin was not less than the increase of binding in the offspring of the untreated and insulin pretreated (24 h before) cells. This meant that tyrphostin had the potency to decrease insulin binding in the offspring generations but the development of imprinting was not influenced.