Uterine gland Uterine gland Tube-like uterine glands, lined by ciliated columnar epithelium, are found in the functional layer of the uterine endometrium. Their appearance varies during the menstrual cycle. During the proliferative phase, uterine glands appear long due to estrogen secretion by the ovaries. During the secretory phase, the uterine glands become very coiled with wide lumens and produce a glycogen-rich secretion. This change corresponds with an increase in blood flow to spiral arteries due to increased progesterone secretion from the corpus luteum. During the pre-menstrual phase, progesterone secretion decreases as the corpus luteum degenerates, which results in decreased blood flow to
Pharmacokinetics of progesterone of the menstrual cycle with LC–MS/MS are 6.7 to 22.2 ng/mL. When the unreliable method of standalone RIA has been used to measure progesterone levels with oral progesterone, far higher peak levels of 6.5 to 10.2 ng/mL, 13.8 to 19.9 ng/mL, and 32.3 to 49.8 ng/mL have been erroneously observed after single 100, 200, and 300 mg doses, respectively. In addition, progesterone levels have been inaccurately measured by RIA as remaining elevated for 12 to 24 hours. Regardless of assay method, peak levels of progesterone following a dose of oral progesterone occur after about 1 to 3 hours. The elimination