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
Progesterone ovaries, the shutting down (whether by natural or chemical means), or removal, of those inevitably causes a considerable reduction in progesterone levels. Previous concentration upon the role of progestogens in female reproduction, when progesterone was simply considered a "female hormone", obscured the significance of progesterone elsewhere in both sexes. The tendency for progesterone to have a regulatory effect, the presence of progesterone receptors in many types of body tissue, and the pattern of deterioration (or tumor formation) in many of those increasing in later years when progesterone levels have dropped, is prompting widespread research into the potential value of maintaining