Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
Dev Biol. 1981 Jun;84(2):455-64. doi: 10.1016/0012-1606(81)90415-2.
Freeze fracture and lanthanum tracer experiments have shown that gap junctions exist throughout folliculogenesis between granulosa cells and growing mouse oocytes (Anderson and Albertini, J. Cell Biol. 71, 680-686, 1976). The following lines of experimentation in the present study suggest that metabolic cooperativity exists between granulosa cells and their enclosed oocytes, i.e., gap junctions are functional, and that in most cases examined, greater than 85% of the metabolites present in follicle-enclosed oocytes were originally taken up by the granulosa cells and transferred to the oocyte via gap junctions: (1) When incubated with various radiolabeled compounds, follicle-enclosed oocytes contained more intracellular radioactivity than did oocytes with no attached granulosa cells (denuded oocytes); (2) for two radiolabeled ribonucleosides examined, the distribution of phosphorylated metabolites in follicle-enclosed oocytes resembled that of granulosa cells and differed significantly from that in denuded oocytes; (3) pulse-chase experiments with radiolabeled ribonucleosides revealed that during the chase period more radioactivity became associated with the follicle-enclosed oocyte; (4) treatments known to disrupt gap junctions in other cell types were effective in reversibly uncoupling metabolic cooperativity between granulosa cells and oocytes; and (5) a series of control experiments using (a) medium conditioned by granulosa cells and (b) cocultures of denuded oocytes and granulosa cells in which physical contact between the two cell types was not permitted demonstrated that contact between follicle cells and oocytes was necessary for observing metabolic cooperativity. Metabolic cooperativity was also found between follicle cells and oocytes in the two culture systems which support growth of mouse oocytes in vitro. The fact that oocytes do not grow well, if at all, in the absence of follicle cells and the large contribution of nutrients apparently furnished to the oocyte by the granulosa cells is consistent with the concept that gap junction mediated metabolic cooperativity between follicle cells and their enclosed oocytes is vital for mammalian oocyte growth.
冷冻断裂和镧示踪实验表明，在卵泡发生过程中，颗粒细胞和生长中的小鼠卵母细胞之间存在缝隙连接（Anderson 和 Albertini，J. Cell Biol. 71, 680-686, 1976）。本研究中的以下实验表明，颗粒细胞与其包裹的卵母细胞之间存在代谢协作，即缝隙连接是功能性的，并且在大多数检查的情况下，卵泡内卵母细胞中存在的超过 85%的代谢物最初是由颗粒细胞摄取，并通过缝隙连接转移到卵母细胞：(1) 当用各种放射性标记化合物孵育时，卵泡内卵母细胞的细胞内放射性比没有附着颗粒细胞的卵母细胞（去颗粒卵母细胞）高；(2) 对于两种放射性标记的核糖核苷，检查卵泡内卵母细胞中磷酸化代谢物的分布类似于颗粒细胞，与去颗粒卵母细胞有显著差异；(3) 放射性标记核糖核苷的脉冲追踪实验表明，在追踪期间，更多的放射性与卵泡内卵母细胞相关；(4) 已知在其他细胞类型中破坏缝隙连接的处理方法在可逆地使颗粒细胞和卵母细胞之间的代谢协作解偶联方面是有效的；(5) 使用（a）颗粒细胞条件培养基和（b）去颗粒卵母细胞和颗粒细胞共培养的一系列对照实验，其中两种细胞类型之间的物理接触不被允许，表明卵泡细胞和卵母细胞之间的接触对于观察代谢协作是必要的。在两种支持体外生长的小鼠卵母细胞的培养系统中，也发现了卵泡细胞和卵母细胞之间的代谢协作。事实上，如果没有卵泡细胞，卵母细胞根本无法很好地生长，并且营养物质显然由颗粒细胞提供给卵母细胞，这与卵泡细胞和它们包裹的卵母细胞之间的缝隙连接介导的代谢协作对于哺乳动物卵母细胞生长至关重要的概念是一致的。
