HISTOLOGICAL AND FUNCTIONAL-CHANGES OF OVIDUCTAL ENDOMETRIUM DURING SEASONAL REPRODUCTIVE-CYCLE OF THE SOFT-SHELLED TURTLE, LISSEMYS PUNCTATA PUNCTATA

Scanning electron and light microscopic studies reveal significant cha nges in the endometrial histophysiology of the soft-shelled turtle Lis semys punctata. punctata during its seasonal reproductive cycle. Scann ing electron microscopy shows the entire oviductal mucosa to be only s lightly folded throughout the non-breeding period (regressive, quiesce nt, preparatory and recrudescent phases). With the onset of the breedi ng phase, the mucosa shows extensive foldings and convolutions. The ad luminal mucosal lining of the non-breeding oviduct is covered by a tal l, dense ciliary bed, interrupted by a few fissures and pits. Microvil li-bordered secretory cells only appear amongst the ciliated cells dur ing the breeding phase. Light microscopic study reveals the mucosal ep ithelium to be low pseudostratified columnar throughout the non-breedi ng period. The breeding epithelium, on the other hand, is tall columna r and does contain clearly distinguishable ciliated and secretory cell types. Submucosal glands only appear for a short period (ovulation to oviposition) in the infundibulum and isthmus regions of the oviduct, but these glands are observed throughout the reproductive cycle in the tube and uterus. The secretory activity of the submucosal glands, whi ch occur only during the peak breeding stages, involves release of ves icular secretory materials through the gland openings. The stimulated endometrial histology and activity during the breeding phase coincide with increased levels of serum estrogen and progesterone, whereas the regressed and inactive state of the endometrium is paralleled by decre ased levels of these ovarian steroids, (C) 1995 Wiley-Liss, Inc.