Attempt to disturb receptor memory in a unicellular (Tetrahymena) model system.

The effect of a hormone-like substance first reaching a receptor is of decisive importance in the unicellular (Tetrahymena) model system. The effect of the similar or dissimilar molecule after the first or second pretreatment depends to a great extent on pretreatment if it was carried out by a similar substance, but it does not depend on it if the agent used for pretreatment was different chemically. Receptor memory developing after hormonal imprinting can thus be disturbed by molecules of similar nature, but the effect of a different molecule--if it acts immediately after the imprinting--cannot be neglected, either.