Proliferative activity of preovulatory follicles and newly formed corpora lutea in cycling rats from late prooestrus to early oestrus.
Ovaries from adult cycling rats were studied from 1600 h on the day of prooestrus to 0700 h on the day of oestrus in order to relate the cyclic hormonal changes to the proliferative activity of preovulatory and postovulatory (i.e. newly-formed corpora lutea) follicles. Proliferative activity was studied by the immunohistochemical demonstration of DNA-incorporated 5-bromodeoxyuridine (BrdU). The proliferative activity of granulosa cells (GC) in large preovulatory follicles showed a centripetal pattern and decreased during prooestrus, reaching a minimum at 2100 h. However, a proliferative wave was found in the GC of preovulatory follicles at 0200 h on the day of oestrus and in those of newly-formed corpora lutea at 0700 h on the day of oestrus. These results suggest that the granulosa cells of preovulatory follicles show maturational changes that followed a different pattern, depending on their location within the follicle, and that the proliferative wave found from 0200 to 0700 h on oestrus is important for the establishment of the number of steroidogenic cells in the cyclic corpus luteum.
Gaytán
F
F
Department of Cell Biology, Faculty of Medicine, University of Cordoba, Spain.
Bellido
C
C
Morales
C
C
Aguilar
E
E
Sánchez-Criado
J E
JE
D000818:Animals; D002455:Cell Division / Q000502:physiology; D003338:Corpus Luteum / Q000166:cytology; D004971:Estrus / Q000502:physiology; D005260:Female; D006107:Granulosa Cells / Q000166:cytology; D007150:Immunohistochemistry; D006080:Ovarian Follicle / Q000166:cytology*; D011359:Proestrus / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar