Two types of three-dimensional structures formed by epithelial cell aggregates from the rat ventral prostate in collagen gel culture. The amount of activated charcoal for absorbing serum.

Cells taken from the rat ventral prostate and cultured formed a tubular structure inside the collagen gel in a medium containing activated charcoal-absorbed serum after a 14-day incubation. This might suggest that the active substances of serum could induce isolated epithelial cells to form such a spherical or tubular structure, depending on the amount of activated charcoal used for the absorption of serum.