Experimental study of hormone receptor development in a unicellular model system.

It was shown earlier that diiodotyrosine (T2) stimulates the growth of Tetrahymena. In the present study clonal populations of Tetrahymena, derived from subcultures propagated in the presence of T2, showed a highly significant increase of intra-clone variance over the control, while inter-clone variation was significant, but not decisive. This suggests that genetic factors play a smaller role in the development of the cell membrane receptor pattern tha the genetic variability of the membrane itself, which seems to account for the stabilization of the adequate receptors on first exposure to a hormone.