Subsurface crypts and interstitial cells in the ovary of the seal (Phoca vitulina vitulina): light and electron microscopic findings.
This morphological study on the ovary of the seal focuses on two structures of special interest: the subsurface crypts and the interstitial cells. Ovaries from 110 seals (from 1,5 months to 12 years) were used. Most of the seals of our study originated from German North Coast, a few from Island. The ovaries were examined by light microscopic as well as by transmission and scanning electron microscopic techniques. The seal's ovary conforms to the basic structure of the ovary of other mammalian species. However, the surface epithelium cell layer lowers itself into an epithelium lined - broadly branching system of subsurface crypts. The size and extent of these crypts and the proliferation of the epithelium appear to be mainly related to the reproductive activity. The ultrastructure of crypt epithelium cells indicates a remarkable metabolic activity. In juvenile ovaries cell buds proliferate from the crypt epithelium and grow as plug-like strands into the cortical stroma. These cells show ultrastructural changes during their proliferation and appear to transform into steroid producing interstitial cells. In the adult seal the interstitial cells are completely differentiated established and, according to their origin, can be divided into epithelial and fibroblastic interstitial cells. It is suggested that a major function of the crypts is the formation of the ovarian blastema with particular reference to ovarian interstitial cells. The intensive proliferation of interstitial cells is in agreement with the extraordinary high level of 350 pmol estrogen/l blood serum.
Mülling
C
C
Department of Veterinary Anatomy, Freie Universität Berlin, Germany. muelling@zedat.fu.berlin.de
Christian
B
B
Budras
K D
KD
D000818:Animals; D002454:Cell Differentiation; D004848:Epithelium / Q000648:ultrastructure*; D005260:Female; D008854:Microscopy, Electron; D010053:Ovary / Q000166:cytology* / Q000254:growth & development; D046048:Seals, Earless; D013799:Theca Cells / Q000648:ultrastructure*