POSITIVE CORRELATION BETWEEN CYTOCHROME-P450 2E1 MESSENGER-RNA LEVEL AND SERUM ESTRADIOL LEVEL IN HUMAN UTERINE ENDOMETRIUM

Most carcinogens are bioactivated by cytochrome P450s (CYPs) and these enzymes within target cells are closely related to susceptibility to cancer. Since extrahepatic CYPs occur typically at much lower levels, the existence and the role of CYP in extrahepatic tissues have been di fficult to assess. In this study, we modified the reverse transcriptas e-polymerase chain reaction (RT-PCR) to evaluate the relative quantiti es of CYP 2E1 mRNA in human endometrium. Total RNA from human endometr ium was reverse-transcribed and coamplified by PCR in the same tube co ntaining both primer pairs of CYP 2E1 and beta-actin. The CYP 2E1 and beta-actin PCR products were 298 and 600 bp, respectively. The restric tion enzyme MboI digested these two products to the predicted size for DNA fragments, demonstrating that both PCR products were specific and CYP 2E1 mRNA exists in human endometrium. CYP 1A1 mRNA was also exami ned, but could not be detected clearly. Adding [alpha-P-32]dCTP to the reaction mixture made it possible to quantify the relative yield of t he CYP 2E1 PCR product in comparison with the p-actin product. The rat io of the yield of the CYP 2E1 PCR product to the beta-actin PCR produ ct could be calculated at a point of 25 cycles of amplification. This ratio and serum estradiol levels were correlated positively (r = 0.654 ; p < 0.05), but no relationship to serum progesterone levels was obse rved.