A dramatic loss of cumulus cell gap junctions is correlated with germinal vesicle breakdown in rat oocytes

Expression of connexin 43 and gap junctional intercellular communication in the cumulus–oocyte complex in sheep

“…In agreement with other researchers, we saw a decrease in GJIC of cumulus cells from large follicles following incubation with LH (Larsen et al 1981(Larsen et al , 1986. Several studies have indicated that in oocytes nearing ovulation, there is a decrease in junctional coupling (Larsen et al 1986, Chen et al 1990). This effect may be due to an unidentified signal from the oocyte to the granulosa/cumulus cells that overrides the usual coupling-enhancing effect of FSH.…”

“…A similar decrease of Cx43 expression in cumulus cells was observed after oocyte maturation in mares (Marchal et al 2003). Previous studies in rodents have established that the onset of meiotic maturation is preceded by the breakdown of gap junctions in the follicles (Larsen et al 1986, Downs 1995, which restricts the flow of signals from follicular cells to the oocyte. However, we observed the presence of Cx43 in COCs with expanded cumulus cells, implying that some level of communication remains between the oocyte and cumulus cells after maturation.…”

“…In addition, exposure of the follicle to LH or human chorionic gonadotropin (hCG) causes the interruption of ionic coupling between granulosa/cumulus cells and the oocyte (Larsen et al 1981(Larsen et al , 1986). In agreement with other researchers, we saw a decrease in GJIC of cumulus cells from large follicles following incubation with LH (Larsen et al 1981(Larsen et al , 1986. Several studies have indicated that in oocytes nearing ovulation, there is a decrease in junctional coupling (Larsen et al 1986, Chen et al 1990).…”

Gap junction and its cytoskeletal undercoats as involved in invagination-endocytosis.

“…There has been accumulating evidence for that GJ membranes are removed from the cell surface by internalization, producing a transient form of annular GJs, in some vertebrate cell systems (Ginzberg and Larsen et al 1986). For the first time, we have described above characteristic network of actin-containing microfilaments in the protruding cytoplasm.…”

Effect of androgen substrates on the steroidogenic pattern of cumulus cells: Correlation with cumulus culture morphology

“…Following the ovulatory surge of lutenizing hormone (LH) and follicle stimulating hormone (FSH), the cumulus-oocyte complex (COC) of the preovulatory follicle undergoes dramatic changes, including cessation of contact between the cells of the cumulus mass and between the oocyte and the cumulus cells, resumption of meiotic maturation, accumulation of hyaluronic acid (1,2), and an increase in progesterone (P4) secretion (3). In small or medium-sized follicles, however, LH is less effective in inducing similar changes in the cumulus mass (4) and oocyte (5,6).…”