The hormones--a model for a new understanding of cell differentiation process. Part I. Differentiation--an individual cell option?

From the beginning I want to explain some interesting notions about cytodifferentiation, these being seen, in my view, like an Instructive Informatory Theory. Then, I tried to present the sustaining arguments for an extracellular differentiation. These arguments reveal that final decision in differentiation process are the receptor molecules. Therefore, I present some actual questions arisen about the correlations between receptors and secondary messengers. The hormones action models are the single way to clear up the vagueness about the nucleus-receptor connection.