Pharmacodynamics of progesterone women, this effect being the result of suppression of the mid-cycle surge in gonadotropin secretion, is 300 mg/day. However, this figure is based on limited clinical data. Conversely, treatment with a high dosage of oral progesterone of 100 mg four times per day (or 400 mg/day total) in men for 10 days that resulted in approximately mid-luteal phase levels of progesterone (7.9–9.4 ng/mL; measured by ) did not cause any change in testosterone levels, suggesting that progesterone has little or no antigonadotropic effect in males at typical clinical dosages. In addition, a study found that administration of 1,000 mg/day oral
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