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
Menstrual cycle use of birth control pills should affect eating behaviour as they minimise or remove the fluctuations in hormone levels. The neurotransmitter serotonin is also thought to play a role in food intake. Serotonin is responsible for inhibiting eating and controlling meal size, among other things, and is modulated in part by ovarian hormones. A number of factors affect whether dieting will affect these menstrual processes: age, weight loss and the diet itself. First, younger women are likely to experience menstrual irregularities due to their diet. Second, menstrual abnormalities are more likely with more weight loss. For example, anovulatory cycles can