Proteins of the rat prostate: I. Preliminary characterization by two-dimensional electrophoresis

The rat prostate consists of three distinct lobes: the ventral, lateral, and dorsal. Proteins in the three lobes of the prostate were studied with the ISO-DALT system for high-resolution two-dimensional electrophoresis. Proteins were detected with ammoniacal silver stain. Comparison of patterns from the three lobes of the prostate of control, noncastrated rats revealed that while there was a remarkable overall similarity, six groups of proteins showed lobe-specific differences. When prostatic regression was induced by castration, androgen-dependent proteins showed a decrease in staining intensity. A group of proteins, with pI 5.0-6.0 and MW 65,000-70,000, was consistently observed only during the active phase of prostatic regression (days 3-7 postcastration). Their presence during this specific interval may play a role in tissue involution.