sn-1,2-diacylglycerol levels increase in progesterone-stimulated Xenopus laevis oocytes.
Full-grown Xenopus laevis oocytes resume meiosis from prophase arrest in response to progesterone stimulation. Recent studies have shown that the tumor promoter, 12-O-tetradecanoylphorbol 13-acetate (TPA), a very potent activator of protein kinase C, can also induce the resumption of meiosis in amphibian oocytes. We have investigated the possibility that sn-1,2-diacylglycerol (DAG), the intracellular activator of protein kinase C, may be involved in the pathway normally used by progesterone. We have found that full-grown oocytes arrested in meiotic prophase contain 48 +/- 5 pmoles DAG/oocyte. This level increases within the first 5 minutes following the addition of progesterone and reaches a maximum of 75 +/- 10 pmoles following 60 minutes of steroid stimulation. Progesterone induces the up-regulation of a Na+/H+ antiport in the plasma membrane of the oocyte causing an increase in pHi following 60 minutes of steroid stimulation. We have found that the addition of 200 microM DAG (1,2-dioctanoylglycerol, diC8) to the culture medium can cause a partial up-regulation of this Na+/H+ pump in the absence of hormonal stimulation. These results suggest that DAG and protein kinase C may be involved in regulating certain aspects of meiotic maturation in progesterone-stimulated Xenopus oocytes.
Wasserman
W J
WJ
Department of Biology, University of Rochester, New York 14627.
Freedman
A B
AB
LaBella
J J
JJ
D000818:Animals; D002855:Chromatography, Thin Layer; D019852:Diacylglycerol Kinase; D004075:Diglycerides / Q000378:metabolism* / Q000502:physiology; D005989:Glycerides / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D008055:Lipids / Q000032:analysis; D009865:Oocytes / Q000378:metabolism*; D009866:Oogenesis / Q000276:immunology; D010770:Phosphotransferases / Q000378:metabolism; D011374:Progesterone / Q000502:physiology*; D011418:Prophase; D011493:Protein Kinase C / Q000502:physiology; D014982:Xenopus laevis
C011439:1,2-diacylglycerol; D004075:Diglycerides; D005989:Glycerides; D008055:Lipids; D011374:Progesterone; D010770:Phosphotransferases; D019852:Diacylglycerol Kinase; D011493:Protein Kinase C