Isolation and preliminary characterization of pig primordial follicles.
An enzymic method for recovering primordial follicles from the pig ovary consists of incubating cortical slices for 2 h with 0.025% collagenase 1A. An average of 185,000 or 419,000 primordial follicles per ovary were recovered from ovaries collected in Cambridge and Kansas, respectively. Following a discontinuous Percoll gradient, primordial follicles can be separated from contaminating somatic cells by mouth pipette or a micromanipulator to collect 100-1500 follicles but for large scale recovery of approximately 30,000 follicles flow cytometry is recommended. Two types of primordial follicles can be distinguished by electron microscopy: peripheral clusters of small oocytes with an incomplete investment of pregranulosa cells and a deeper region of individual oocytes surrounded by a complete layer of pregranulosa cells. The viability of the purified primordial follicles is attested by their ability to synthesize proteins for at least 12 h after incubation with [35S]methionine. Moreover, the primordial follicles showed several polypeptide bands in common with mature oocytes especially with Mr of 60,000-90,000 but with considerable differences from somatic cells.
Greenwald
G S
GS
Department of Physiology, University of Kansas Medical Center, Kansas City 66103.
Moor
R M
RM
D000818:Animals; D003584:Cytological Techniques; D004586:Electrophoresis; D005260:Female; D005434:Flow Cytometry; D008854:Microscopy, Electron; D006080:Ovarian Follicle / Q000648:ultrastructure; D010053:Ovary / Q000032:analysis / Q000166:cytology / Q000648:ultrastructure; D011506:Proteins / Q000032:analysis; D013552:Swine
D011506:Proteins