Differences in nonhistone protein changes in rat ventral and dorsolateral prostate during sexual maturation

Protein profiles of benign hypertrophic prostate: stroma-abundant distribution of BPH-associated nonhistone proteins

Mechanically isolated epithelium and stroma from benign hypertrophic prostates were highly pure on the basis of histochemical and biochemical criteria. By electrophoretic analyses, whole cellular and nuclear proteins were compared among whole tissues, epithelium, and stroma. The characteristic protein profiles of benign hypertrophic prostates were reflected in the electrophoretic patterns of the stroma. Two-dimensional gel electrophoretic patterns of the epithelium were different from those of the stroma with exception of about 18 major spots that were common to both fractions. Of the protein species separated, 35K/6.7 (molecular weight/pI) and 36K, which was composed of two species with pI of 4.4 and 4.6, were abundant in the epithelium and stroma, respectively. Nuclei prepared from whole tissues of benign hypertrophic prostates contained three kinds of nonhistone proteins (NHP) closely associated with benign prostatic hypertrophy (BPH); 42 K-NHP, 55 K-NHP and 190 K-NHP. Electrophoretic analysis of the nuclear proteins revealed that all the BPH-associated nonhistone proteins were abundantly distributed in the nuclei of the stroma.

Growth factors in the prostate

Certain local tissue factors, such as growth factor, in addition to androgens, are involved in the prostate growth. The prostate contains two types of growth factors capable of stimulating DNA synthesis in BALB/3T3 cells. They were divided into low affinity (LoA) type and high affinity (HiA) type by a different affinity for heparin-Sepharose. HiA-type growth factor is further classified into acidic HiA and basic HiA types. Acidic HiA type could be purified from the Dunning tumor (R 3327), a rat prostatic adenocarcinoma, and has a molecular weight of about 19,000 and a pI of about 3.8. Basic HiA type could be isolated from the tissues of human benign prostatic hypertrophy and has a molecular weight of about 12,000 and a pI of about 10.5. They are inactivated by heat and acid treatments. Acidic HiA type appears to be involved in growth of the rat prostate epithelium, and LoA type growth factor is possibly relevant to reproductive physiology because of its coexistence with "probasin," a major secretory protein in the dorsolateral prostate having a strong affinity for spermatozoa.

Lobe-specific distribution of a 20,000-dalton nonhistone protein in the dorsolateral prostate of rats

Distribution of an androgen-dependent, 20,000-dalton nonhistone protein with a pI of about 11.5 (20K-NHP) was examined by electrophoretic techniques. Nuclei of the brain, liver, spleen, skeletal muscle, lung, and thymus of rats contained a negligible amount of 20K-NHP, whereas 20K-NHP was distinctly detectable, in different relative amounts, in the nuclei of the male accessory sex organs, with the dorsolateral prostate having the highest relative content (100%), followed by the coagulating gland (approximately equal to 16%), the ventral prostate (approximately equal to 6%), and the seminal vesicle (approximately equal to 2%). There were heterogeneous distributions of cytosol components, acid phosphatase isozymes, and nonhistone proteins in the dorsolateral prostate. Zinc was localized in the lateral lobe, and fructose and glucose were in the dorsal lobe. Cytosol proteins with pI 7.5, 8.2, and 8.5 were abundant in the dorsal lobe, and proteins with pI 7.4 and 8.0 in the lateral lobe. Acid phosphatase isozymes with pI 7.1, 7.4, 7.7, and 8.0 were abundantly distributed in the lateral lobe. Of the nonhistone proteins, 20K-NHP showed the highest content both in the lateral lobe and in the dorsal lobe. It was found that 20K-NHP was more abundantly distributed in the lateral lobe (maximally four times higher) than in the dorsal lobe. The heterogeneous distribution of 20K-NHP in the dorsolateral prostate was strikingly similar to that of zinc. It appears, therefore, that 20K-NHP is closely related to dorsolateral prostate zinc content.

Comparison of subcellular proteins of normal prostate, benign prostatic hypertrophy, and prostatic cancer: presence of BPH-associated nonhistone proteins

Proteins in the cytosol, postnuclear particulate, and nuclear fractions from seven specimens of normal prostate from bladder cancer patients, 14 specimens of benign hypertrophic prostate (BPH), and three specimens of cancerous prostate were analyzed and compared by SDS-polyacrylamide slab gel electrophoresis. Abundant protein species in the cytosol fractions were 60K (species having a molecular weight of about 60,000) and 42K; their relative contents were about 35% for 60K and about 12% for 42K. In the postnuclear particulate fraction, 42K was the most abundant (about 10% of the total). The contents of these major protein species were similar in specimens of normal and diseased prostates. In addition, there are marked similarities in the electrophoretic patterns for all the protein (24-29 species) in the cytosol and postnuclear particulate fractions of the human prostate, except for four minor species in the cytosol fraction. Of the nuclear proteins, the content of core histones (H2A, H2B, H3, and H4) was fundamentally similar among all the specimens, whereas the content of H1 histone was different from one specimen to another. The most remarkable and significant difference was that the 42K-NHP (nonhistone protein having a molecular weight of about 42,000), 55K-NHP, and 190K-NHP concentrations were significantly higher in BPH than in normal and cancerous prostates.