Translator Disclaimer
1 September 2000 Maturation/M-Phase Promoting Factor: A Regulator of Aging in Porcine Oocytes
Kazuhiro Kikuchi, Kunihiko Naito, Junko Noguchi, Arata Shimada, Hiroyuki Kaneko, Masakane Yamashita, Fugaku Aoki, Hideaki Tojo, Yutaka Toyoda
Author Affiliations +
Abstract

Deterioration in the quality of mammalian oocytes during the metaphase-II arrest period is well known as “oocyte aging.” Oocytes in which aging has occurred are called aged oocytes, and these oocytes show enhanced activation and higher fragmentation rates after parthenogenetic activation. Previously we showed that porcine aged oocytes had low maturation/M-phase promoting factor (MPF) activity, and we suggested that this low MPF activity contributed at least in part to the aging phenomena. In the present study, we examined the relationship between MPF activity and these aging phenomena by artificially regulating MPF activity in porcine metaphase-II-arrested oocytes. Since we have shown recently that aged porcine oocytes contain abundant phosphorylated inactive MPF, so-called pre-MPF, we used vanadate and caffeine, which affect the phosphorylation status of MPF, to regulate MPF activity. Incubation of 48-h-matured oocytes with vanadate for 1 h increased the phosphorylation of MPF and decreased MPF activity. The parthenogenetic activation and fragmentation rates were significantly increased compared with those of control oocytes. Conversely, treatment of 72-h-cultured aged oocytes with caffeine (last 10 h of culture) decreased the level of pre-MPF and elevated MPF activity. These oocytes revealed significantly lower parthenogenetic activation rates and a lower percentage of fragmentation than did untreated aged oocytes. These results indicate that not only the increased ability for parthenogenetic activation but also the increased fragmentation rate observed in porcine aged oocytes may be attributable in part to the gradual decrease in MPF activity during prolonged culture. Control of MPF phosphorylation with these agents may allow for some degree of manipulation of oocyte aging.

Kazuhiro Kikuchi, Kunihiko Naito, Junko Noguchi, Arata Shimada, Hiroyuki Kaneko, Masakane Yamashita, Fugaku Aoki, Hideaki Tojo, and Yutaka Toyoda "Maturation/M-Phase Promoting Factor: A Regulator of Aging in Porcine Oocytes," Biology of Reproduction 63(3), 715-722, (1 September 2000). https://doi.org/10.1095/biolreprod63.3.715
Received: 24 January 2000; Accepted: 1 April 2000; Published: 1 September 2000
JOURNAL ARTICLE
8 PAGES


Share
SHARE
KEYWORDS
aging
meiosis
RIGHTS & PERMISSIONS
Get copyright permission
Back to Top