Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0042755 (masculinization)
 2,562 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The androgen receptor (AR) mediates androgen action determining male sexual phenotypes and promotion of spermatogenesis. Mutations in the AR cause various degrees of androgen resistance resulting in a range of androgen insensitivity syndromes. A single copy gene in the X chromosome encodes the AR. The gene contains a polymorphic triple repeat sequence [(CAG)n] with 9-36 repeats in the normal population, and displays ethnic dependence. In vitro, there is an inverse correlation between CAG repeat length and AR function. Associations exist between short alleles and prostate cancer in men or clinical hyperandrogenism in women. Expansion of the CAG tract > 40 repeats leads to spinal bulbar muscular atrophy (SBMA, Kennedy disease), an adult onset neurodegenerative disease that also presents with low virilization and spermatogenetic defects. The disease may show evidence of anticipation (increasing severity with succeeding generations accompanying further expansion of repeat length). Twelve studies involving Singaporean, Australian, North American and Japanese men reported a relationship between AR CAG repeat length and male infertility, whereas 10 studies, most of them European, found no association. Differences in hereditary or acquired factors in these populations may explain the equivocality. However, statistical methods, sample sizes, study definition and control populations, in addition to laboratory methods vary widely within the published papers, and could affect the results and conclusions. Current data is insufficient to conclude whether IVF patients who display AR CAG expansion may transfer infertility or premutation of neurodegenerative disease to their descendants. We recommend screening of AR CAG repeat length, at least in those populations where an association between repeat length and infertility could be found.
 ...
PMID:[Androgen receptor and male infertility]. 1552 1

Androgen replacement therapy is a promising strategy for the treatment of frailty; however, androgens pose risks for unwanted effects including virilization and hypertrophy of reproductive organs. Selective Androgen Receptor Modulators (SARMs) retain the anabolic properties of androgens in bone and muscle while having reduced effects in other tissues. We describe two structurally similar 4-aza-steroidal androgen receptor (AR) ligands, Cl-4AS-1, a full agonist, and TFM-4AS-1, which is a SARM. TFM-4AS-1 is a potent AR ligand (IC(50), 38 nm) that partially activates an AR-dependent MMTV promoter (55% of maximal response) while antagonizing the N-terminal/C-terminal interaction within AR that is required for full receptor activation. Microarray analyses of MDA-MB-453 cells show that whereas Cl-4AS-1 behaves like 5alpha-dihydrotestosterone (DHT), TFM-4AS-1 acts as a gene-selective agonist, inducing some genes as effectively as DHT and others to a lesser extent or not at all. This gene-selective agonism manifests as tissue-selectivity: in ovariectomized rats, Cl-4AS-1 mimics DHT while TFM-4AS-1 promotes the accrual of bone and muscle mass while having reduced effects on reproductive organs and sebaceous glands. Moreover, TFM-4AS-1 does not promote prostate growth and antagonizes DHT in seminal vesicles. To confirm that the biochemical properties of TFM-4AS-1 confer tissue selectivity, we identified a structurally unrelated compound, FTBU-1, with partial agonist activity coupled with antagonism of the N-terminal/C-terminal interaction and found that it also behaves as a SARM. TFM-4AS-1 and FTBU-1 represent two new classes of SARMs and will allow for comparative studies aimed at understanding the biophysical and physiological basis of tissue-selective effects of nuclear receptor ligands.
 ...
PMID:Identification of anabolic selective androgen receptor modulators with reduced activities in reproductive tissues and sebaceous glands. 1984 49