Role of epithelial-stromal interactions in the control of gene expression in the prostate: an hypothesis.

An hypothesis that explains the effects of stromal-epithelial interactions on the mechanism of action of androgens is presented. This hypothesis proposes the existence of three factors, two growth factors referred to as "stromally derived growth factor" (SDGF) and "epithelially derived growth factor" (EDGF), and one inhibiting factor, "epithelially derived inhibiting factor" (EDIF), which together modulate the replicative and transcriptional processes of the prostate. The hypothesis attempts to explain the well documented modulation of epithelial morphology and function by the stromal cells of the prostate that occurs during development. It also describes the role of each of the factors in the mature prostate, and suggests that in the adult the interaction between the stroma and epithelium, while still significant does not greatly influence the action of androgens, which exert their effects via the classical steroid receptor mechanism.