Ultrastructure and morphometry of ovarian follicles in the armadillo Chaetophractus villosus (Mammalia, Dasypodidae).

CODÓN, S. M.; ESTECONDO S.; GALÍNDEZ, E.J.; CASANAVE E.B.

BRAZILIAN JOURNAL OF BIOLOGY

Instituto Internacional de Ecologia

Lugar: São Carlos SP - Brazil; Año: 2001 vol. 61 p. 485 - 499

1519-6984

ABSTRACT Ultrastructural and morphometric changes in oocyte and surrounding granulosa cells during armadillo follicular growth are described. Primordial, intermediary, early and late primary, secondary, tertiary and preovulatory Graafian follicles were found. From primordial to Graafian follicle, granulosa cells increase in height, become multilayered while fluid-filled spaces arise among them in the tertiary follicle stage. As the follicle expands the oocyte is located eccentrically and grows in size. From primordial to secondary stage organelles develop in number and complexity and many vesicles start arising in the cytoplasm at the secondary stage. From tertiary follicle stage the number of mitochondria decreases. In follicular cells, secreting-related organelles expand, but mitochondrial number decreases according to the follicle expansion. Intercellular junctions between both cell types increase. Themorphometrical study shows a biphasic pattern of oocyte and follicle growth. The morphological baseline here provided will be essential for further comprehension of the reproductive biology in armadillos. Key words: ovarian follicles, armadillo, Chaetophractus villosus, Dasypodidae, reproduction.