Starfish oocytes arrest at metaphase of the first meiotic division (MI arrest) in the ovary and resume meiosis after spawning into seawater. MI arrest is maintained by lower intracellular pH (pH(i)) and release from arrest by cellular alkalization. To elucidate pH(i) regulation in oocytes, we cloned the starfish (Asterina pectinifera) Na(+)/H(+) exchanger 3 (ApNHE3) expressed in the plasma memb...

When somatic cell nuclei are injected into enucleated unfertilized eggs they very soon cease RNA synthesis (Gurdon & Brown, 1965; Gurdon. 1967 a), and commence DNA synthesis (Graham, Arms & Gurdon, 1966). By means of such experiments it has been shown (i) that components of living egg cytoplasm can substantially change the nature of nuclear activity, (ii) that nuclear activity is altered in suc...

Objective Paracrine disruption of growth factors in women with polycystic ovarian syndrome results in production of low quality oocyte, especially following ovulation induction. The aim of this study was to investigate the effects of metformin (MET), N-acetylcysteine (NAC) and their combination on the hormonal levels and expression profile of GDF-9, BMP-15 and c-Kit, as hallmarks of oocyte qual...

Brief exposure to some pesticides, applied during a sensitive window for the neural regulation of ovulation, will block the preovulatory surge of LH and, thus, delay ovulation. Previously, we have shown that a single i.p. injection of 50 mg/kg of thiram, a dithiocarbamate fungicide that decreases norepinephrine synthesis, on proestrus (1300 h) suppresses the LH surge and delays ovulation for 24...

The HCO(3)(-)/Cl(-) exchanger is quiescent in the unfertilized mouse egg but is highly active in regulating intracellular pH in the early embryo and required for normal development. We show here that the HCO(3)(-)/Cl(-) exchanger is active in first meiotic prophase (GV) oocyte but inactivated during meiotic metaphase before the MI to MII transition. Reactivation does not occur until the activat...

We have developed a competitive reverse transcription-polymerase chain reaction (RT-PCR) sensitive enough to detect and quantify as little as 2-fold differences in gene expression in individual oocytes and embryos throughout human preimplantation development. This RT-PCR assay can be tailored for the examination of any specific gene and so will give a unique insight into human preimplantation d...

F O R fifty years considerable attention has been devoted to a comparative study of the respiratory metabolism of eggs prior to and after fertilization (Warburg, .1908). With regard to sea-urchin eggs two trends may be recognized. First, variations of oxygen consumption were examined, and although striking increases in respiration were noted in some cases, it was soon recognized that this was n...