Progesterone stimulates the expression of aminopeptidase A/angiotensinase in human choriocarcinoma cells

In human placenta aminopeptidase A (APA), a principal enzyme that converts angiotensin II to angiotensin III, seems to be involved in angiotensin II m etabolism during pregnancy. In this study, we investigated the possible eff ects of progesterone and estrogen on APA mRNA and protein levels in chorioc arcinoma cells as a model for placenta. By RNase protection assay, progeste rone induced higher APA mRNA levels than estrogen at the same concentration . Progesterone exhibited dose-dependent stimulation of APA mRNA, 1.8-fold i ncrease at 10(-6) M for 24 h treatment. Progesterone at 10(-6) M increased APA mRNA levels within 12 h and in time-dependent fashion up to 24 h. Fluor escence-activated cell sorting analysis and measurements of APA activities revealed the induction of APA protein by progesterone. Expression of proges terone receptors (PR) and glucocorticoid receptors (GR) were determined in these cells by RT-PCR, which suggested that the progesterone's actions migh t be displayed through PR and/or GR. These findings may serve as a useful m odel to study the effects of progesterone on angiotensin II metabolism in p lacenta, although the physiological validity of these studies remains to be clarified. (C) 2001 Harcourt Publishers Ltd.