Document Detail


Postnatal regulation of germ cells by activin: the establishment of the initial follicle pool.
MedLine Citation:
PMID:  16930587     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Mammalian females enter puberty with follicular reserves that exceed the number needed for ovulation during a single lifetime. Follicular depletion occurs throughout reproductive life and ends in menopause, or reproductive senescence, when the follicle pool is exhausted. The mechanisms regulating the production of a species-specific initial follicle pool are not well understood. However, the establishment of a follicular reserve is critical to defining the length of reproductive cyclicity. Here we show that activin A (rh-ActA), a known regulator of follicle formation and growth in vitro, increased the number of postnatal mouse primordial follicles by 30% when administered to neonatal animals during the time of germline cyst breakdown and follicle assembly. This expansion in the initial follicle pool was characterized by a significant increase in both germ cell and granulosa cell proliferation. However, the excess follicles formed shortly after birth did not persist into puberty and both adult rh-ActA- and vehicle-treated animals demonstrated normal fertility. A follicle atresia kinetic constant (k(A)) was modeled for the two groups of animals, and consistent with the empirical data, the k(A) for rh-ActA-treated was twice that of vehicle-treated animals. Kinetic constants for follicle formation, follicle loss and follicle expansion from birth to postnatal day 19 were also derived for vehicle and rh-ActA treatment conditions. Importantly, introduction of exogenous rh-ActA revealed an intrinsic ovarian quorum sensing mechanism that controls the number of follicles available at puberty. We propose that there is an optimal number of oocytes present at puberty, and when the follicle number is exceeded, it occurs at the expense of oocyte quality. The proposed mechanism provides a means by which the ovary eliminates excess follicles containing oocytes of poor quality prior to puberty, thus maintaining fertility in the face of abnormal hormonal stimuli in the prepubertal period.
Authors:
Sarah K Bristol-Gould; Pamela K Kreeger; Christina G Selkirk; Signe M Kilen; Robert W Cook; Jingjing L Kipp; Lonnie D Shea; Kelly E Mayo; Teresa K Woodruff
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't     Date:  2006-06-17
Journal Detail:
Title:  Developmental biology     Volume:  298     ISSN:  0012-1606     ISO Abbreviation:  Dev. Biol.     Publication Date:  2006 Oct 
Date Detail:
Created Date:  2006-09-25     Completed Date:  2006-12-04     Revised Date:  2014-09-15    
Medline Journal Info:
Nlm Unique ID:  0372762     Medline TA:  Dev Biol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  132-48     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Activin Receptors / metabolism
Activins / metabolism*,  pharmacokinetics,  pharmacology,  physiology*
Animals
Animals, Newborn
Cell Proliferation
Female
Fertility*
Follicle Stimulating Hormone / blood
Germ Cells / physiology
Mice
Models, Biological
Oocytes / drug effects,  physiology
Ovarian Follicle / drug effects,  physiology*
Ovary / cytology,  metabolism*
Signal Transduction
Stem Cells / physiology
Grant Support
ID/Acronym/Agency:
HD007068/HD/NICHD NIH HHS; P01 HD021921/HD/NICHD NIH HHS; P01 HD021921/HD/NICHD NIH HHS; U54 HD041857/HD/NICHD NIH HHS; U54 HD041857-09/HD/NICHD NIH HHS; U54 HD41857/HD/NICHD NIH HHS; U54-HD28934/HD/NICHD NIH HHS
Chemical
Reg. No./Substance:
0/activin A; 104625-48-1/Activins; 9002-68-0/Follicle Stimulating Hormone; EC 2.7.11.30/Activin Receptors

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


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