Aromatization of C-19-steroid (androstenedione; delta 4 A) and C-19 norsteroid (19-nortestosterone; NT) was measured in human placenta, liver and adipose tissues. The tissue homogenates (0.5 approximately 1.0 g w.w.) were incubated with [6, 7-3H]-delta 4 A or [6, 7-3H]-NT (10 microCi) and NADPH (1 mg/ml of 0.1M-bisodium phosphate buffer) at 37 degrees C for 2 hr in air. The enzyme reaction was terminated with 3 volumes of ethyl acetate, and [4-14C]-estrone (E1) and [4-14C]-estradiol-17 beta (E2) (10,000 dpm, 250 micrograms) were added in the incubated sample. The extract with ethyl acetate was subjected to Bio-Rad AG1-X2 column chromatography. The phenol fraction thus obtained was subjected to thin layer chromatography (TLC) (cyclohexane-ethyl acetate = 2:1, V/V and chloroform-ethyl ether = 4:1, V/V). The resulting E1 and E2 were finally isolated by co-crystallization to constant specific activity and 3H/14C ratio of crystal crops. In human placental microsomes, estrogen formation from delta 4 A and NT was 8.10 and 1.84 pmol E1 + E2/hr/mg protein, respectively. In adult liver homogenates, only E1 (35-76 fmol/hr/g) was formed from delta 4 A, but E1 and E2 were formed (70 and 31-61 fmol/hr/g, respectively) from NT. On the other hand, adipose tissue had the ability to aromatize delta 4 A to E1 (38-69 fmol/hr/g), but its ability to aromatize NT was significantly lower than that for delta 4 A. These results show that NT is readily aromatized to estrogens in the liver.
An equimolar mixture of 3H-E1-S2 and 14C-E1 was injected in one shot into the inferior vena cava near the heart of female Japanese monkey. Following the injection, blood was collected from the aortic arch at intervals of 15 s over a period of 10 min. The concentration of radioactivities in the whole blood and serum was measured. The metabolites were analyzed by DEAE-Sephadex A-25 column chromatography, enzyme hydrolysis, thin layer chromatography and paper chromatography. Both radioactivities of 3H-E1-S and 14C-E1 rapidly decreased in the first 90-s serum sample. The 3H/14C ratio in the 0-15-s serum sample was 5 times higher than the initial ratio of injected compounds. The radioactivities in the serum gradually decreased after 90 s of injection. The 3H/14C ratio in the pulmonary tissue was very low after collecting the final blood sample. This result shows that the most of 3H-E1-S passed through the lung and the larger part of 14C-E1 remained in the lung following injection of these materials. So, it is probable that E1-S is in a form to be carried in the general circulation.
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