Lipid composition in epithelium and stroma of human benign prostatic hyperplasia.

The lipid composition and concentration in human benign prostatic hyper-plasia (BPH) were investigated. The reason was to shed some light onto the lipid environment of cellular membranes, in which the epithelial and stromal 5 alpha-reductase of the human prostate have apparently to be embedded in order to gain an active state. The phospholipids were found to be the major portion (67% +/- 1.1) of total lipids in whole BPH homogenate, followed by cholesterol (29% +/- 1.1) and glyceride glycerols (4% +/- 0.9). In BPH epithelium, the lipid concentration related to wet weight and to protein was two to three-fold higher than in stroma. Assigning the lipid concentration on a per-cell basis (i.e., related to DNA), a significantly lower lipid concentration was found in the epithelium as compared to the stroma. In the stroma, a significantly higher phospholipid and lower cholesterol portion were found than in the epithelium. Moreover, sphingomyelin was found to comprise a higher portion in stromal than in epithelial phospholipids, whereas the percentage of phosphatidylserine was higher in the epithelial phospholipids. We discuss whether the significant differences in lipid concentration and composition between the epithelium and stroma of human BPH could have an impact on the activity of the membrane-bound 5 alpha-reductase, or whether such differences in the lipid environment are due to a different hormonal milieu in the epithelium and stroma of BPH.