title: Measurement of HPRT activity in the human unfertilized oocyte and pre-embryo.
abstract: The hypoxanthine phosphoribosyl transferase (HPRT) and adenine phosphoribosyl transferase (APRT) activities in individual non-fertilized human eggs and in human pre-embryos (4-cell to blastocyst stage) have been analysed. A wide spread of activities was observed, the mean values of which decline with time post-ovulation for both eggs and advancing pre-embryonic stages. The variation in activities was less in groups of eggs or pre-embryos recovered from a single ovulatory cycle. The activity of HPRT, but not of APRT, was readily detectable in single 4-cell and 8-cell blastomeres. When pre-embryos at various preimplantation stages were exposed to alpha-amanitin, to block transcription of mRNA from the pre-embryonic genome, no clear effect on HPRT activity was observed. It is concluded that the HPRT and APRT activities measured in the pre-embryos studied here are likely to be maternally inherited, and that use of a direct assay for HPRT activity for the pre-implantation diagnosis of Lesch-Nyhan disease would be premature.
authors.affiliation: Department of Obstetrics and Gynaecology, University of Cambridge, U.K.
authors.forename: P R
authors.initials: PR
authors.lastname: Braude
authors.forename: M
authors.initials: M
authors.lastname: Monk
authors.forename: S J
authors.initials: SJ
authors.lastname: Pickering
authors.forename: A
authors.initials: A
authors.lastname: Cant
authors.forename: M H
authors.initials: MH
authors.lastname: Johnson
mesh_terms: D000228:Adenine Phosphoribosyltransferase / Q000378:metabolism*; D000546:Amanitins / Q000494:pharmacology; D047108:Embryonic Development / Q000187:drug effects; D005260:Female; D006801:Humans; D007041:Hypoxanthine Phosphoribosyltransferase / Q000032:analysis*; D066298:In Vitro Techniques; D007926:Lesch-Nyhan Syndrome / Q000175:diagnosis; D009865:Oocytes / Q000032:analysis*; D010430:Pentosyltransferases / Q000378:metabolism*; D011247:Pregnancy; D011296:Prenatal Diagnosis / Q000379:methods; D014158:Transcription, Genetic / Q000187:drug effects; D015053:Zygote / Q000032:analysis*
chemical_list: D000546:Amanitins; D010430:Pentosyltransferases; D000228:Adenine Phosphoribosyltransferase; D007041:Hypoxanthine Phosphoribosyltransferase