Volumen 52 #2 | Año 2015 Volver Indice
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  Pathophysiological Implications of Androgen Receptor. Mutations, Polymorphisms and Pathologic Associations  
  Authors: Levalle OA, Lalosa S.  
  Androgens are synthesized and secreted into the blood stream for circulation mainly as a form of testosterone. These hormones affect a number of diverse responses in a variety of peripheral target tissues. Their biological actions are mediated in the peripheral target cell via the androgen receptor (AR). The AR complex is a ligand bound nuclear receptor, combining general transcriptional complex with a large number of receptor-associated co-regulators. The AR is a member of the steroid hormone receptor family, which is found in a variety of tissues, and changes throughout development, aging, and malignant transformation. Recently, cloning and characterization of several AR co-regulators have allowed for cellular and molecular analysis of many different aspects of androgen physiology and pathophysiology.
After entering its target cells and before it can exert its specific function, To will either be metabolized by aromatase into estradiol in the hypothalamus, bone and many other tissues, or be metabolized by 5 α-reductase into dihydrotestosterone in most of the male reproductive organs.
Androgen receptor plays a critical role in the function of several organs including primary and accessory sexual organs, skeletal muscle, vascular smooth muscle cell, endothelial cells, central nervous system, adipose tissue, and bone, which makes it a desirable therapeutic target.
Numerous types of androgen receptor mutations have been linked to a wide range of clinical manifestations, from the partial androgen insensitive syndrome (PAIS) to complete testicular feminization, prostate cancer, polycystic ovary syndrome, male infertility, Klinefelter syndrome, etc.
Besides, polymorphism of the AR glutamine tract has been reported to reduce receptor function and increase the risk of male infertility and defective spermatogenesis. When expansion exceeds 40 repeats, it causes a rare neuromuscular disorder, spinal and bulbar muscular atrophy (Kennedy's disease), which is also associated with decreased virilization, testicular atrophy, reduced sperm production, and infertility. These results indicate a direct relationship between the length of this AR-specific variable polymorphic region and defective sperm maturation caused by decreased functional competence of the AR. However, a correlation can not be established between the variable CAG (polyglutamine)-repeat and the presence of illness in all the different ethnic groups.
In this review, we provide a brief overview of genomic androgens/AR actions, as well as of the regulation of their co-regulators. We also explore several complex aspects of the molecular biology of AR and co-regulators that are related to clinical diseases.

Rev Argent Endocrinol Metab 52:79-107, 2015
No financial conflicts of interest exist.
  Key words: androgen receptor, gene mutations, gene polymorphisms, androgens, gestosterone  
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