Testosterone metabolism in the human endometrium : a combination of metabolic (mass spectrometry) and enzyme expression (RT-PCR)

• Main Author: Taylor, Angela Elizabeth
• Published: Swansea University 2009
• Online Access: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.752206

Localised steroid metabolism is important in proliferative disorders of the endometrium. The metabolism of testosterone, an important precursor in endometrial disorders, was investigated by mass spectrometry and RT-PCR (real-time polymerase chain reaction), allowing determination of steroid metabolites and expression of steroid converting enzymes; aromatase, 17P-HSD1, 2,4,5,7,8,(hydroxysteroid dehydrogenase) and 5AR1, 2 (alpha reductase). Samples were derived from cell lines (Ishikawa, HEC-1A, HEC-1B, RL95-2, COV434), and biopsies; fertile, endometriosis, poly-cystic ovary syndrome (PCOS), endometrial hyperplasia, unexplained infertility, endometrial polyp. Optimum mass spectrometry techniques, determined using steroid standards, were LC/MS for androgens and LC/MS/MS for oestrogens, following dansyl-chloride derivatisation. GC/MS was less sensitive. The route of testosterone metabolism varied in the cell lines and clinical biopsies, the major metabolite was correlated with high expression of 5AR1 or 17p-HSD2, 4 and 8. If DHT (dihydrotestosterone) was produced high basal expression of 5AR1 was observed and if androstenedione was produced high basal expression of HSD2, 4 or 8 was observed. A mixture of DHT and androstenedione was correlated with expression of 5AR1 and 17P-HSD2, 4 or HSD 8. Changes in enzyme expression were correlated with changes in steroid concentration after testosterone treatment, as follows: 1. Increased 5AR1 expression was correlated with increased DHT concentration in Ishikawa, HEC-1B, COV434, PCOS, endometriosis, stromal hyperplasia and ovarian cyst biopsies. 2. Increased expression of 5AR2 was correlated with increased androsterone concentration in fertile and unexplained infertility biopsies. 3. Increased 17p-HSD5 expression was correlated with increased testosterone concentration in HEC-1A cells. 4. Increased aromatase expression was correlated to increased oestradiol and oestrone concentrations in a hyperplasia biopsy. Analysis of a range of enzymes and steroids produced testosterone metabolism maps of the endometrium (and associated disorders) highlighting steroids which could contribute to endometrial disorders and viable enzyme target(s) for inhibition (5AR1,17P-HSD2, 4, 8).