Uterine glandular regeneration during the follicular phase in the marsupial Trichosurus vulpecula

Abstract

The uterine luteal phase in T, vulpecula extends from day 8 to day 16 of the 26-day oestrous cycle. During this time both uteri are in an active secretory phase which is particularly pronounced in the basal gland cells, where both apocrine and holocrine-type release of a component of the uterine milk occurs. During the follicular phase which follows the luteal phase, uterine glandular regeneration takes place. Prior to mitotic activity in the uterine endometrium, a regenerative process occurs whereby the basal parts of the glands are surrounded and progressively enclosed by differentiating stromal cells, forming a double gland. The mode of regeneration is completed by mitotic activity in the cells of the outer gland while the inner or old gland cells progressively break up, leaving a lumen within the newly formed uterine gland.