metribolone and Hyperplasia

Heterogeneity in human androgen receptor (hAR) expression in prostate cancer is considered to be implicated in tumor progression. hAR expression was therefore studied immunohistochemically in localized and locally progressive, hormone refractory (HR) prostate cancer. Because altered functional activity of the hAR may be due to changes in the structural integrity of the hAR gene, exons 2 to 8 of the hAR gene were assessed for mutations by single-strand conformation polymorphism (SSCP) analysis and exon 1 was analyzed for the size of the CAG repeat. The hormone binding capacity, a prerequisite for ligand-regulated receptor function, was determined by a ligand binding assay. Coexpression of the hAR and prostate-specific antigen (PSA) was studied by a sequential double immunoenzymatic staining to verify whether PSA expression is a parameter of hAR function. Almost all human prostatic carcinomas revealed heterogeneous hAR expression, regardless of tumor differentiation and progression. Putative predominance of hAR-negative tumor areas in HR prostate cancer was not observed. No hAR gene mutations or major changes in the CAG repeat were found in the 18 HR carcinomas or in the 9 control samples. Moreover, all selected hAR-expressing cancers were able to bind the synthetic androgen methyltrienolone (R1881). Immunoenzymatic double staining revealed even PSA expression in hAR-negative tumor areas. PSA immunohistochemistry in human prostatic carcinomas therefore is of no use in determining hAR functional activity. Thus, most prostatic carcinomas, even when progressed to a state of hormone insensitivity, contain a structurally intact hAR gene, heterogeneously expressed with retained androgen binding capacity.

Topics: Antibodies, Monoclonal; Base Sequence; Carcinoma; DNA Primers; Exons; Gene Expression; Hormones; Humans; Hyperplasia; Immunoenzyme Techniques; Male; Metribolone; Molecular Sequence Data; Mutation; Prostate; Prostate-Specific Antigen; Prostatectomy; Prostatic Neoplasms; Receptors, Androgen; Repetitive Sequences, Nucleic Acid

Liver is responsive to sex hormones. The role of androgens in normal human liver function is not well understood, although androgens have been implicated in several liver diseases. Because the human hepatic androgen receptor has not been adequately characterized, we analyzed cytosolic and nuclear fractions from normal human liver of both sexes for androgen-binding activity using multipoint saturation analysis with the androgenic radioligand methyltrienelone (R1881). Both cytosolic and nuclear fractions of both sexes displayed high affinity R1881 binding (dissociation constants = nanomolar range). The R1881 binding in both fractions is highly specific in that potent androgens compete well, and the antiandrogens hydroxyflutamide and cyproterone acetate show partial competition; other nonandrogenic steroid hormones do not compete. The cytosolic R1881 receptor displays physicochemical characteristics of androgen receptors in other tissues in that it is retained by heparin-Sepharose and by DNA cellulose after activation, and it displays a molybdate-stabilized 8S form on sucrose gradients and a 7.3-nm species on gel filtration chromatography. Receptor activity was also quantitated in specimens of hepatic adenoma, focal nodular hyperplasia and metastatic carcinoma to the liver and in samples of adjacent histologically normal specimens when available. In general, both the diseased and normal portions of the livers from the patients with hepatic adenoma and metastatic carcinoma to the liver, but not focal nodular hyperplasia, demonstrated reduced total androgen-receptor activity as compared with liver from normal individuals.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Androgen Antagonists; Androgens; Binding, Competitive; Cell Nucleus; Cytosol; Female; Humans; Hyperplasia; Liver; Liver Diseases; Liver Neoplasms; Male; Metribolone; Middle Aged; Receptors, Androgen