Document Detail

Equine chorionic gonadotropin regulates luteal steroidogenesis in pregnant mares.
MedLine Citation:
PMID:  9780310     Owner:  NLM     Status:  MEDLINE    
The onset of eCG secretion in pregnant mares coincides with an increase in luteal steroid production and a relative shift toward androgen and estrogen synthesis. However, a cause-effect relationship between eCG and the shift in luteal steroidogenesis has not been demonstrated. In this study, we have investigated the effect of eCG on steroid production by the corpus luteum (CL) during equine pregnancy. All mares were supplemented with 44 mg altrenogest (a progestogen) per day on Days 18-50. Increasing doses of eCG were administered on Days 26-28, before the onset of endogenous eCG secretion, to four mares with and four mares without a functional CL (prostaglandin F2alpha administered on Day 18). Four mares with a functional CL received no exogenous eCG. In eCG-treated mares without a functional CL, progestin, androstenedione, and estrogen concentrations did not significantly increase after exogenous eCG administration or endogenous eCG secretion. In eCG-treated mares with a functional CL, progestin and estrogen production increased significantly after exogenous eCG administration and endogenous eCG secretion, whereas androstenedione concentrations tended to increase following exogenous eCG and increased significantly following endogenous eCG secretion. In mares with a functional CL that did not receive exogenous eCG, progestin and estrogen concentrations increased and androstenedione concentrations tended to increase only after the onset of endogenous eCG secretion. These data demonstrate that the increase in luteal steroidogenesis that coincides with the onset of eCG secretion is induced by eCG and results in an increase in luteal androgen and estrogen synthesis. Our findings support the hypothesis that eCG has a luteotropic action in pregnant mares.
P F Daels; B A Albrecht; H O Mohammed
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Biology of reproduction     Volume:  59     ISSN:  0006-3363     ISO Abbreviation:  Biol. Reprod.     Publication Date:  1998 Nov 
Date Detail:
Created Date:  1998-12-22     Completed Date:  1998-12-22     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0207224     Medline TA:  Biol Reprod     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1062-8     Citation Subset:  IM    
Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, New York 14853, USA.
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MeSH Terms
Androstenedione / biosynthesis
Chorionic Gonadotropin / administration & dosage,  pharmacology*,  secretion
Corpus Luteum / drug effects*,  metabolism*
Estrogens / biosynthesis
Gestational Age
Horses / physiology*
Progestins / biosynthesis
Steroids / biosynthesis*
Reg. No./Substance:
0/Chorionic Gonadotropin; 0/Estrogens; 0/Progestins; 0/Steroids; 63-05-8/Androstenedione

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

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