Abstract
The aim of this study was to examine the effects of 17-alpha-hydroxyprogesterone caproate (17OHP-C) on the activity and expression of several common hepatic cytochrome P450 (CYP) enzymes.
Primary human hepatocytes were pretreated with vehicle or 17OHP-C (0.1 and 1 μmol/L) for 72 hours, then incubated for 1 hour with a cocktail of CYP substrates. The activity of various CYP enzymes was determined by measuring the formation of the metabolites of specific CYP substrates, using liquid chromatography–tandem mass spectrometry. The messenger RNA expression of various CYP enzymes was determined by real-time polymerase chain reaction.
In primary cultures of human hepatocytes, 17OHP-C minimally altered the activity or messenger RNA levels of CYP1A2, CYP2C9, CYP2D6, and CYP3A. However, 17OHP-C at 1 μmol/L increased CYP2C19 activity by 2.8-fold (P < .01) and CYP2C19 expression by 2.4-fold (P < .001), compared with vehicle-treated cells. A strong positive correlation between activity and expression of CYP2C19 was also observed (r = 0.9, P < .001).
The activity and expression of hepatic CYP2C19 was significantly increased by 17OHP-C in primary cultures of human hepatocytes. This suggests that exposure to medications that are metabolized by CYP2C19 may be decreased in pregnant patients receiving 17OHP-C. Metabolism of substrates of CYP1A2, CYP2C9, CYP2D6, and CYP3A are not expected to be altered in patients receiving 17OHP-C.