Development of naked growing mouse oocytes in vitro

Abstract

Half grown oocytes were released from follicles of 7-day-old mouse ovaries during overnight culture. Naked oocytes free of attached follicular cells were cultured in MEM plus 10% fetal calf serum over the developing monolayer of ovarian cells. Oocytes increased in diameter for a period of at least a week at 1.6 micron per day, or 70% of the in vivo growth rate. The ultrastructure of cytoplasmic organelles in cultured growing oocytes was normal. During the second week, about 35% underwent spontaneous fragmentation, and at least 10-20% resumed meiotic maturation. We conclude that a significant fraction of naked oocytes reached a functional state comparable to that of normal full grown oocytes at a rate approaching the in vivo rate. Free oocytes with attached cells grew to a larger average diameter than naked oocytes, and incorporated 3H-leucine 75% more rapidly. Naked oocytes cultured in the absence of ovarian cells did not grow, and died when pyruvate was omitted from the medium. Naked oocytes did not grow when cultured over primary mouse fibroblasts, L-cells, CHO cells, or hepatoma cells. Naked oocytes separated from the monolayer of ovarian cells by a 0.7 mm layer of agar grew at 60% of the rate of control oocytes.

Exogenous lactate is essential for metabolic activities in isolated rat spermatocytes and spermatids

“…It has been shown that testicular LDH-X catalyses preferentially lactate oxidation and is localized in cytosol and mitochondria (Blanco, Burgos, Gérez de Burgos & Montamat, 1976;. This, as well as the localization of mitochondria in early round spermatids close to the cell surface (Clermont & Rambourg, 1978) (Palombi et al, 1979 (Donahue & Stern, 1968 (Biggers, Whittingham & Donahue, 1967;Zeilmaker & Verhamme, 1974;Hillensjö, Hamberger & Ahrén, 1975;Eppig, 1976), but growing oocytes can survive in the absence of pyruvate when cultured in the presence of follicular granulosa cells (Baran & Bachvarova, 1977;Eppig, 1977;Bachvarova, Baran & Tejblum, 1980 …”

Mammalian oocyte maturation

“…In vitro studies have shown that specialized membrane contacts with follicular cells are necessary to oocyte growth : growth is only maintained when oocytes are cultured encompassed by follicular cells but not on follicular cell monolayer, unless removal of the zona allows coupling (Buccione et al, 1987). FSH or estradiol does not seem beneficial (mouse, Eppig, 1977Eppig, , 1979Bachvarova et al, 1980). The favorable effect of these hormones on the percentage of competent oocytes in young hypophysectomized rats (Bar-Ami and Tsafriri, 1981) is probably related to the favorable effect of these hormones on the whole ovary and particularly on the follicular cells rather than to a specific action on the oocytes.…”

Cellular origin, hormonal regulation and biochemical characteristics of polypeptides secreted by Graafian follicles of sheep

“…It Moor, 1983). The importance of this communication is demonstrated by the inability of isolated oocytes to grow in vitro (Eppig, 1979;Bachvarova et al, 1980) and by the negligible developmental ability of oocytes denuded of cumulus cells before in-vitro maturation (Crosby et al, 1981 …”