Document Detail

Follicular development, ovulation, fertilization and fetal development in tenrecs (Tenrec ecaudatus).
MedLine Citation:
PMID:  4040574     Owner:  NLM     Status:  MEDLINE    
Reproduction in female tenrecs was studied on Praslin Island (4 degrees 20'S, 55 degrees 45'E) in the Seychelles from November 1977 to September 1980. Dissection and histological examination of reproductive tracts revealed that each ovary is encapsulated in a bursa. Polyovular follicles were abundant and contained up to 5 oocytes. The occurrence of more implanted fetuses than corpora lutea (CL) indicated successful polyovuly in 25% of pregnancies. No antrum was observed during follicular growth at oestrus, and follicles were relatively small at maturation, reaching a maximum diameter of 570 microns. Ovulation involves a gentle extrusion of the granulosa and ovum into the periovarian space. Spermatozoa were abundant in the female reproductive tract including the periovarian space at oestrus. Spermatozoa penetrated the loosely-packed theca of mature follicles and were present in CL, indicating that intrafollicular fertilization may occur. The relatively small CL formed by eversion, reaching a maximum size after implantation. Fusion of up to four CL occurred in the ovaries of 41% of pregnant females. Polyovulation in the tenrec was confirmed by the occurrence of 10.4 +/- 0.5 (mean +/- s.e.m.) CL and 9.7 +/- 0.5 (mean +/- s.e.m.) implantations. Resorption occurred in 74% of 19 dissectable pregnancies, occurring in both uterine horns in 26% of pregnancies. Coefficients of variation in weights of fetuses in each litter were 10.0-26.8%, with the largest value corresponding to 273% variation in fetus weights. Litter size in the Seychelles tenrecs was smaller than in the same species in Madagascar (17.1 +/- 1.9 implantations) where the tenrec is native.
M E Nicoll; P A Racey
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of reproduction and fertility     Volume:  74     ISSN:  0022-4251     ISO Abbreviation:  J. Reprod. Fertil.     Publication Date:  1985 May 
Date Detail:
Created Date:  1985-09-04     Completed Date:  1985-09-04     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0376367     Medline TA:  J Reprod Fertil     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  47-55     Citation Subset:  IM    
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MeSH Terms
Corpus Luteum / anatomy & histology
Embryonic and Fetal Development*
Insectivora / physiology*
Litter Size
Oocytes / growth & development
Ovarian Follicle / anatomy & histology,  growth & development*
Ovary / anatomy & histology
Pregnancy, Animal*
Spermatozoa / anatomy & histology

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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