Document Detail

The effect of exogenous estradiol benzoate and altrenogest on uterine and ovarian blood flow during the estrous cycle in mares.
MedLine Citation:
PMID:  15037001     Owner:  NLM     Status:  MEDLINE    
In recent years, a positive relationship between genital perfusion and fertility has been established; in species other than horses, uterine and ovarian perfusion was improved by exogenous estrogen but impaired by exogenous progestin. The goal of the present study was to investigate the effect of exogenous estrogen and progestin on uterine and ovarian blood flow in cycling mares. Five Trotter mares were examined daily during three estrous cycles. Mares were given no treatment, altrenogest (0.044 mg/kg BW) orally from Day 0 (ovulation) to Day 14 and estradiol benzoate (5mg i.m.) on Days 0, 5, and 10, in three cycles, respectively. There was no difference ( P > 0.05 ) in the length of untreated versus estrogen-treated cycles ( 22.8 +/-1.3 days and 23.2 +/= 1.5 days, respectively), but cycle length was increased (P < 0.05) in progestin-treated cycles (26.0 +/- 1.2). To facilitate comparisons among cycles with different lengths, data from Days 0 to 15 (diestrus) and from Days -6 to -1 (estrus) were analyzed. Transrectal Doppler sonography was used to evaluate blood flow in both uterine arteries and in the ovarian artery ipsilateral to the preovulatory follicle during estrus and ipsilateral to the corpus luteum during diestrus. Blood flow was assessed semiquantitatively using the pulsatility index (PI); high PI values indicated high resistance and a low perfusion and vice versa. An immediate effect of treatments occurred only after the administration of estradiol benzoate on Day 0; uterine PI values decreased (P < 0.05) between Days 0 and 1 and estrogen-treated mares but increased (P < 0.05) at the corresponding time in untreated cycles. Mean PI values for the uterine and ovarian arteries during both diestrus and estrus were higher (P < 0.05) in estrogen-treated versus untreated mares. Furthermore, mean uterine PI values during diestrus and estrus were higher (P< 0.05) in altrenogest-treated versus untreated mares. Neither estrogen nor altrenogest treatments had a significant immediate effect on ovarian PI values. Compared to untreated cycles, mean ovarian PI values were elevated (P < 0.05) only in the estrus following altrenogest administration. In conclusion, exogenous estrogen and progestin both decreased genital perfusion in cycling mares.
Heinrich Bollwein; Birgit Kolberg; Rudolf Stolla
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Theriogenology     Volume:  61     ISSN:  0093-691X     ISO Abbreviation:  Theriogenology     Publication Date:  2004 Apr 
Date Detail:
Created Date:  2004-03-23     Completed Date:  2004-06-18     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0421510     Medline TA:  Theriogenology     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1137-46     Citation Subset:  IM    
Department of Animal Reproduction, Veterinary College, University of Munich, Königinstr. 12, 80539 Munich, Germany.
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MeSH Terms
Arteries / physiology
Blood Flow Velocity / drug effects
Estradiol / analogs & derivatives*,  pharmacology*
Estrous Cycle*
Horses / physiology*
Ovary / blood supply*
Progesterone Congeners / pharmacology
Pulsatile Flow
Trenbolone / analogs & derivatives*,  pharmacology*
Uterus / blood supply*
Reg. No./Substance:
0/Progesterone Congeners; 10161-33-8/Trenbolone; 50-28-2/Estradiol; 50-50-0/estradiol 3-benzoate; 850-52-2/altrenogest

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

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