RÉSUMÉ
The ability of the human normal uterine cervix and cervical carcinoma to interconvert estradiol-17β and estrone is due to the activity of 17β-hydroxysteroid dehydrogenase (17β-HSD). Human cervical 800 x g supernatant fractions were analyzed by incubating with 3H-estradiol (20 nM) and NAD (0.25 ตmol) in 50 mM Tris buffer at pH 8.0. The incubation was terminated by adding 1 ml of 100% methanol and the supernatants were evaporated in air. The dry residues were resuspended in methanol, and aliquots were chromatographed in silica gel thin layer plates in benzene : ethanol (9 : 1, V : V). The 17β-HSD activity was determined from the amount of estrone formed and expressed as nanomoles of estrone formed/mg protein X h. The 17β-HSD activity was higher in normal cervix than in cervical carcinoma. Estradiol-17β added to incabation mixture caused a slight increase in enzyme activity only in cervical carcinoma while it had no effect in normal tissues. Progesterone administration increased 17β-HSD activity in some cases of normal and carcinoma cervix. These results suggest that changes in enzyme concentrations may play a physiologic role in the regulation of tissue levels of estradiol-17β.
RÉSUMÉ
Beta-aminoisobutyric acid (βAIBA); a degradation product of thymine in both deoxyribonucleic (DNA) and transfer ribonucleic acid (tRNA) was determined in single urine specimens from 65 normal healthy subjects and 60 patients with cancer of various organs by thin layer chromatography. The normal control value from both males and females was 74.01+25.81 nmol βAIBA/µmol creatinine. The excretion levels were significantly increased in patients with several types of tumor (146.79+137.64 nmol βAIBA/µmol creatinine). Increased levels of βAIBA excretion may reflect changes in DNA metabolism or increased turnover of tRNA in tumor. The changes of βAIBA excretion levels were also studied in cancer patients before radiotherapy. The levels returned to normal when they were in remission but remained high in patients whose clinical conditions were not improved. The same results were also found in patients with choriocarcinoma during chemotherapy. Therefore, determination of urinary βAIBA level could be used as a potential biological marker for monitoring the effectiveness of therapy in malignancies.