title: In utero and in vitro proteinase activity during the Mesocricetus auratus embryo zona escape time window.
abstract: The goal of the present study was to investigate proteinase activity in uterine flushates collected during the zona loss time window (68-80 h post-egg activation) in both pregnant and pseudopregnant hamsters and in culture medium conditioned by hatching blastocysts. Several prominent enzyme activities appeared in all pregnant and pseudopregnant uterine flushates. However, only a 45, 43 x 10(-3) M:(r) doublet coincided with the zona loss time window; these bands were absent outside of this time window and were not found in conditioned medium. In medium conditioned by hatching blastocysts, enzyme activity was represented by a 70, 65 x 10(-3) M:(r) doublet identical to a doublet seen in all uterine flushates collected and in serum. There were 12 pregnant and 8 pseudopregnant uterine flushates that were capable of zona lytic activity in vitro (positive bioassays). Of these positive bioassays, five pregnant and four pseudopregnant uterine flushates exhibited the 45, 43 x 10(-3) M:(r) doublet (correlative positive bioassays). These data suggest that there is an important uterine contribution to blastocyst escape from the zona pellucida, consisting of proteinases secreted during a finite time window prior to blastocyst attachment that are different from the proteinases responsible for the zona lytic activity in vitro.
authors.affiliation: Department of Biology, University of Southern Colorado, Pueblo, Colorado 81001, USA. dgonz@uscolo.edu
authors.forename: D S
authors.initials: DS
authors.lastname: Gonzales
authors.forename: B D
authors.initials: BD
authors.lastname: Bavister
authors.forename: S A
authors.initials: SA
authors.lastname: Mese
mesh_terms: D000818:Animals; D001681:Biological Assay; D001755:Blastocyst / Q000502:physiology; D006224:Cricetinae; D017077:Culture Media, Conditioned; D004622:Embryo, Mammalian / Q000502:physiology*; D010450:Endopeptidases / Q000378:metabolism*; D005260:Female; D008647:Mesocricetus; D011247:Pregnancy; D011555:Pseudopregnancy / Q000201:enzymology; D007507:Therapeutic Irrigation; D014599:Uterus / Q000201:enzymology; D015044:Zona Pellucida / Q000502:physiology* / Q000648:ultrastructure
chemical_list: D017077:Culture Media, Conditioned; D010450:Endopeptidases