ISSN:
1432-0738
Keywords:
Chick embryo
;
Yolk sac
;
Mixed-function oxidase MFO
;
Metabolic activation
;
Aldrinepoxidase
;
7-Ethoxycoumarin-O-deethylase
;
7-Ethoxyresorufin- O-deethylase
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract Since the chick embryoin ovo is susceptible to the action of some agents needing metabolic activation we studied the development of the activity of cytochrome P450-dependent monooxygenases in embryo/fetal tissue. The activities of aldrinepoxidase (AE), 7-ethoxycoumarin-O-deethylase (ECOD) and 7-ethoxyresorufin-O-deethylase (EROD) were measured in whole embryos, liver and yolk sac tissue of the chick embryo during developmentin ovo from day 4 to day 15 of incubation (DI). In yolk sac tissue enzyme activities could be detected from DI 4 on. While EROD activity was only marginally developed, AE and ECOD activities were more pronounced in the earlier developmental period and showed a clear decrease by the time the liver activities rose. With the methods used AE activity could be measured in the homogenate of the whole embryo proper from DI 4 on while EROD and ECOD activity was not detectable before DI 6 or DI 7, respectively. In liver tissue enzyme activities of the three monooxygenases studied developed to a considerable degree from DI 9 on and tended to exhibit maximum values around DI 11–13. Studies on monooxygenase activities in extra-embryonically located tissues have not been published until now. The importance of the yolk sac as a metabolically relevant organ during embryogenesis is pointed out in this study.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01974398
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