Document Detail

Vertebrate extracellular preovulatory and postovulatory egg coats.
MedLine Citation:
PMID:  18614703     Owner:  NLM     Status:  MEDLINE    
Extracellular egg coats deposited by maternal or embryonic tissues surround all vertebrate conceptuses during early development. In oviparous species, the time of hatching from extracellular coats can be considered equivalent to the time of birth in viviparous species. Extracellular coats must be lost during gestation for implantation and placentation to occur in some viviparous species. In the most recent classification of vertebrate extracellular coats, Boyd and Hamilton (Cleavage, early development and implantation of the egg. In: Parkes AS (ed.), Marshall's Physiology of Reproduction, vol. 2, 3rd ed. London: Longmans, Green & Co; 1961:1-126) defined the coat synthesized by the oocyte during oogenesis as primary and the coat deposited by follicle cells surrounding the oocyte as secondary. Tertiary egg coats are those synthesized and deposited around the primary or secondary coat by the maternal reproductive tract. This classification is difficult to reconcile with recent data collected using modern molecular biological techniques that can accurately establish the site of coat precursor synthesis and secretion. We propose that a modification to the classification by Boyd and Hamilton is required. Vertebrate egg coats should be classed as belonging to the following two broad groups: the preovulatory coat, which is deposited during oogenesis by the oocyte or follicle cells, and the postovulatory coats, which are deposited after fertilization by the reproductive tract or conceptus. This review discusses the origin and classification of vertebrate extracellular preovulatory and postovulatory coats and illustrates what is known about coat homology between the vertebrate groups.
Ellen Menkhorst; Lynne Selwood
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Publication Detail:
Type:  Comparative Study; Journal Article; Review     Date:  2008-07-09
Journal Detail:
Title:  Biology of reproduction     Volume:  79     ISSN:  0006-3363     ISO Abbreviation:  Biol. Reprod.     Publication Date:  2008 Nov 
Date Detail:
Created Date:  2008-10-27     Completed Date:  2008-12-11     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0207224     Medline TA:  Biol Reprod     Country:  United States    
Other Details:
Languages:  eng     Pagination:  790-7     Citation Subset:  IM    
Department of Zoology, University of Melbourne, Parkville, Victoria 3052, Australia.
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MeSH Terms
Extracellular Matrix / physiology*
Ovum / cytology,  physiology*
Vertebrates / physiology*

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