Progesterone and is responsible for approximately 70% of cytochrome P450-mediated progesterone metabolism. Other routes include 6α-, 16α-, and 16β-hydroxylation. However, treatment of women with ketoconazole, a strong CYP3A4 inhibitor, had minimal effects on progesterone levels, producing only a slight and non-significant increase, and this suggests that cytochrome P450 enzymes play only a small role in progesterone metabolism. In women, progesterone levels are relatively low during the preovulatory phase of the menstrual cycle, rise after ovulation, and are elevated during the luteal phase, as shown in diagram below. Progesterone levels tend to be less than 2 ng/mL prior to ovulation, and greater
Progesterone carboxymethyloxime potassium salt) showed water solubility that was increased by more than four orders of magnitude relative to progesterone (solubility = 9.44 mol/L and 0.0006 mol/L, respectively). In addition, it showed an "in vitro" terminal half-life in rat liver microsomes that was 363-fold longer than that of progesterone (half-life = 795.5 minutes and 2.2 minutes, respectively). As such, P4-3-CMO could have both improved absorption and increased metabolic stability relative to progesterone. However, the compound has not been further assessed nor studied in humans. Progesterone carboxymethyloxime Progesterone carboxymethyloxime, or progesterone 3-("O"-carboxymethyl)oxime (P4-3-CMO), is a progestin which was never marketed. It is an