Ultrastructure of human fertilization

Dvořák, Milan; Kopečný, V.

doi:10.1007/978-1-4613-3867-3_15

Cited by 5 publications

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Human nonovulatory oocyte‐cumulus complexes: Ultrastructure, macromolecular synthesis, and developmental potential

Kopečný¹,

Dvořák

Pilka

et al. 1984

Gamete Research

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Human nonovulatory oocyte-cumulus complexes were obtained from large antral follicles 34 h after the injection of hCG. Their ultrastructure, RNA and protein synthesis, and the ability of oocyte maturation and subsequent fertilization in vitro werc the subject of this study. The oocyte nucleus was situated in the cell periphery, possessing one or two dense nucleoli. Intranucleolar vacuoles were sometimes present. Mitochondria and smooth endoplasmic reticulum were the most abundant cytoplasmic structures. The number of cortical granules was rather low. Cumulus cells showed responsiveness to exogeneous hCGiendogeneous LH stimulation as morphologic signs of the oocyte-cumulus uncoupling and o f the early luteinization. Furthermore, the oocytes were capable of meiotic maturation in vitro, and following subsequent in vitro insemination the majority of them were penetrated by spermatozoa. However, polyspermy was detected in most cases, and clcavage was not achieved. A developmental defect of nonovulatory oocytes was suggested by an extremely low level of RNA synthesis while continuing active protein synthesis by nonovulatory oocytes was demonstrated. In contrast, the associated cumulus cells synthesized both RNA and protein, suggesting that the majority of granulosa cells of the nonovulatory follicles was probably unaltered. It is hypothesized that the development of nonovulatory follicles after induction of ovulation might reveal the developmental pattern which would lead, in some cases, to ovulation of nonviable human oocytes both in stimulated and natural cycles.

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