Involvement of purine nucleotide synthetic pathways in gonadotropin‐induced meiotic maturation in mouse cumulus cell‐enclosed oocytes

SM Downs - Molecular Reproduction and Development …, 1997 - Wiley Online Library
oocyte maturation in meioti- successive periods of meiotic arrest and resumption durcally
arrested cumulus cell-enclosed oocytes. Oo-cytes ing the ontogeny of the oocyte. The …

Purine control of mouse oocyte maturation: evidence that nonmetabolized hypoxanthine maintains meiotic arrest

SM Downs - Molecular Reproduction and Development, 1993 - Wiley Online Library
… In B, cumulus cell-enclosed oocytes were maintained in meiotic arrest 17-18 h in … Cumulus
cell-enclosed oocytes were maintained in meiotic arrest by varying concentrations of a …

Maintenance of murine oocyte meiotic arrest: uptake and metabolism of hypoxanthine and adenosine by cumulus cell-enclosed and denuded oocytes

SM Downs, DL Coleman, JJ Eppig - Developmental biology, 1986 - Elsevier
… follicle cells or the oocyte to other purine derivatives which, … , cumulus cell-enclosed and
denuded oocytes were isolated … , cumulus cell-enclosed oocytes were isolated and washed in …

Metabolite supply in oocytes of Nereis virens: role of nucleosides

U Hoeger, N Rebscher, G Geier - Reproductive Strategies and …, 1999 - Springer
oocyte growth. This overview focusses on the role of exogenous purine nucleosides for the
growing oocytes. … male and female germ cells are not enclosed in a nutritive (follicular) tissue …

Maintenance of meiotic arrest in mouse oocytes by purines: modulation of cAMP levels and cAMP phosphodiesterase activity

SM Downs, SAJ Daniel, EA Bornslaeger… - Gamete …, 1989 - Wiley Online Library
… Hypoxanthine maintained 80% of cumulus cell-enclosed oocytes in … oocyte-cumulus cell
complexes, yet this purine nucleoside increased the inhibitory effects of hypoxanthine on oocyte

Induction of mouse oocyte maturation in vivo by perturbants of purine metabolism

SM Downs, JJ Eppig - Biology of reproduction, 1987 - academic.oup.com
… metabolic pathways in vivo might induce the resumption of oocyte maturation. To test this …
enzymes in the purine metabolic pathways. Cumulus cell-enclosed oocytes were isolated from …

Meiotic induction in cumulus cell-enclosed mouse oocytes: involvement of the pentose phosphate pathway

SM Downs, PG Humpherson… - Biology of …, 1998 - academic.oup.com
… Fully grown mammalian oocytes spontaneously resume meiotic maturation when removed
… -enclosed oocytes can be blocked in prophase I if the medium is supplemented with purines

Uptake and metabolism of adenosine mediate a meiosis‐arresting action on mouse oocytes

SM Downs - Molecular Reproduction and Development …, 1999 - Wiley Online Library
… To measure uptake by cumulus cell– enclosed oocytes (CEOs), … end of culture and the
oocytes were washed and processed for … Oocytes were cultured for 3 hr and purines were added …

Culture conditions affect meiotic regulation in cumulus cell‐enclosed mouse oocytes

SM Downs, AM Mastropolo - Molecular Reproduction and …, 1997 - Wiley Online Library
… on oocyte maturation and de novo purine synthesis. Cumulus cell-enclosed oocytes were
… We next determined whether FSH-stimulated de novo purine synthesis is compromised in L-…

High performance liquid chromatography analysis of hypoxanthine metabolism in mouse oocyte-cumulus cell complexes: Effects of purine metabolic perturbants

SM Downs - Biology of reproduction, 1994 - academic.oup.com
… The initial 1-h incubation assured that the drugs used had ample time to act before introduction
of the radiolabeled purine. For oocyte maturation, cumulus cell-enclosed oocytes were …