Male patients on testosterone replacement therapy, those with a past medical or family history of prostate cancer, those currently or with a history of using
5a-reductase inhibitors (i.e., finasteride, dutasteride, and high-dose saw palmetto), or those with low
5a-reductase activity as previously measured on a urine hormone profile are all candidates for further evaluation.
Primary prevention of PCa has focused on chemoprevention, vitamin supplements (selenium, Vitamin E, and Vitamin C), and
5a-reductase inhibitors (finasteride and dutasteride).
Thigpen et al., Molecular Genetics of Steroid
5a-Reductase 2 Deficiency, 90 J.
Morton, "Inhibition of
5a-reductase in genital skin fibroblasts and prostate tissue by dietary lignans and isoflavonoids," Journal of Endocrinology, vol.
The oligomeric stilbenes have been shown have many interesting biological activities such as: as inhibitor of
5a-reductase (Hirano et al., 2001), scavenger of superoxide (Tanaka et al., 2000) and cytotoxic agents (Seo et al., 1999).
A second category of medicines includes what are termed the
5a-reductase inhibitors, including Proscar and Avodart.
Finasteride, an inhibitor of
5a-reductase, inhibits the conversion of testosterone to dihydrotestosterone, the primary androgen in the prostate, and may reduce the risk of prostate cancer.
Biochemical tests, imaging, chromosomal studies, and genetic testing were used to arrive at a diagnosis of
5a-reductase deficiency (5ARD).
(46) Repeating for emphasis: As more insulin is applied, more
5a-reductase is made.
The Risks and Benefits of
5a-Reductase Inhibitors for Prostate-Cancer Prevention.
Possible explanations are a lack of
5a-reductase activity or, more likely, deficient progesterone as substrate.
They compared 2312 Icelandic men who underwent medical or surgical management for BPH (including treatment with
5a-reductase inhibitors, which are known to lower the PSA concentration) vs 33 779 presumed-healthy Icelandic men.
The biologically active androgen dihydrotestosterone is produced from testosterone in the prostate by the action of type 1 and type 2 steroid
5a-reductase isoenzymes.
The ratio of 5a-THF:THF served to assess activity of the cortisol-catabolizing enzyme
5a-reductase relative to 5[beta]-reductase.
In other words, testosterone is a target hormone itself as well as a circulating prohormone for several target tissues that possess the converting enzymes
5a-reductase and aromatase.
