Author/Editor     Eminović, Izet
Title     Genska variabilnost steroidne 5alfa-reduktaze tipa 1 pri človeku
Type     monografija
Place     Ljubljana
Publisher     Medicinska fakulteta
Publication year     1999
Volume     str. 69
Language     slo
Abstract     Virilization in mammals is mediated by two steroid hormones, testosterone and dihydrotestosterone. Both hormones bind to a typical steroid hormone receptor, the androgen receptor, and activate genes containing androgen/responsive DNA sequences. Dihydrotestosterone is in fact a potent androgen with physiological roles distinct from those of testosterone. Androgen target tissues contain an enzyme activity (steroid 5a-reductase) capable to reducing testosterone to dyhidrotestosterone. Product of this enzyme accumulate in the nuclei of responsive cells. The studies of an inborn error of male phenotypic sexual differentiation, termedes steroid 5a-reductase type II deficiency, provide genetic proof of the crucial role of dihydrotestosterone in androgen action. Excessive production of 5a-dihydrotestosterone is the major cause of many androgen-related disorders, such as prostate cancer, benign prostatic hyperplasia, acne, female hirsutism and male pattern baldness. The key enzyme in androgen action is the steroid 5a-reductase. To date, two genes encoding 5a-reductase isozymes are known, designated as type I (SRDSA1) and type II (SRD5A2), and a type I pseudogene (SRDSAP1). These enzymes have different biochemical in pharmacological properties. Screening of genital and extragenital tissues in males in females elucidated the distribution of these*isozymes. The presence of both enzymes was established for a number of tissues, including the central nervous system, the urogenital, respiratory and gastrointestinal tract, skin and endocrine system. We have tested the possible involvement of steroid 5a-reductase on elevated levels of DHT in hyperandrogenic females. Using primer pairs specific for human SRDSAl, we have amplified from genomic DNA and analyzed with SSCP the coding part of the entire gene. (absract truncated at 2000 characters)
Descriptors     HYPERANDROGENISM
TESTOSTERONE 5-ALPHA-REDUCTASE
TESTOSTERONE
STANOLONE
DNA PROBES
POLYMORPHISM, SINGLE-STRANDED CONFORMATIONAL
POLYMERASE CHAIN REACTION
BASE SEQUENCE
HYBRIDIZATION