Distribution and cyclic change of aromatase cytochrome P-450 activity in human uteri

Activities of aromatase cytochrome P-450 in the columnar epithelial region (CE), squamous epithelial region (SE) and connective tissue (CT) of uterine cervix, and endometrium (EM) during the menstrual cycle were determined using [4-14C] and [1 beta-3H]androstenedione. Aromatase activities in the proliferative phase (n = 8) were 15.0 +/- 7.9, 10.9 +/- 10.3, 9.4 +/- 10.6 and 8.0 +/- 7.3 (mean +/- SD) fmol/h/mg protein in CE, SE, CT and EM, respectively, and aromatase activities in the secretory phase (n = 6) were 31.5 +/- 7.6, 19.1 +/- 7.1, 5.6 +/- 4.6 and 6.3 +/- 1.5 fmol/h/mg protein, respectively. The results show that the aromatase activities in these regions in the proliferative phase were not significantly different from each other. On the other hand, the aromatase activity in the secretory phase was significantly higher in CE than in any other regions (P less than 0.05), and significantly higher in SE than in CT or EM (P less than 0.05). There was no significant difference in aromatase activity between CT and EM. By comparison of aromatase activity between these two phases, the activity in CE was significantly higher in the secretory phase than in the proliferative phase (P less than 0.05), but no significant difference was observed in other regions.