title: The PGF2α agonists luprostiol and d-cloprostenol reliably induce luteolysis in luteal phase mares without evoking clinical side effects or a stress response.
abstract: In the present study we have evaluated a possible stress reaction in response to two different PGF2α analogs-luprostiol and D-cloprostenol--and their effects on estrous cycle characteristics. In a cross-over-design eight mares received in alternating order either luprostiol (Treatment LUP; 3.75 mg im), D-cloprostenol (Treatment CLO; 22.5μg im) or saline (Treatment CON; NaCl 0.9% 0.5ml im) on day 8 after ovulation. Injection of either LUP or CLO, but not of CON resulted in a significant decline of progesterone concentration in plasma to baseline concentrations within two days (time: p<0.001, treatment: p<0.01, time × treatment: p<0.05). The treatment to ovulation interval was significantly shorter in LUP and CLO than in CON cycles (LUP: 9.4 ± 0.4 d; CLO: 9.4 ± 1.3 d; CON: 16.1 ± 0.8 d; p<0.001). Injection of either LUP or CLO, but not of CON significantly increased salivary cortisol concentration (immediately before injection: CON 1.3 ± 0.2, LUP 1.4 ± 0.3, CLO 1.4 ± 0.3 ng/ml; 60 min after injection: CON 1.0 ± 0.3, LUP 8.0 ± 1.4, CLO 4.2 ± 0.7 ng/ml; time: p<0.01, treatment: p<0.001, time × treatment: p<0.001). Heart rate decreased over time (p<0.05) independent of treatment and no changes in heart rate variability were detected. Injection of the PGF2α analogs CLO and LUP reliably induced luteolysis and apart from a transient increase in salivary cortisol concentration no signs of a physiological stress response or apparent side effects occurred.
authors.affiliation: Artificial Insemination and Embryo Transfer, Vetmeduni Vienna, Vienna, Austria. Electronic address: juliane.kuhl@vetmeduni.ac.at.
authors.forename: Juliane
authors.initials: J
authors.lastname: Kuhl
authors.affiliation: Artificial Insemination and Embryo Transfer, Vetmeduni Vienna, Vienna, Austria.
authors.forename: Christina
authors.initials: C
authors.lastname: Nagel
authors.affiliation: Artificial Insemination and Embryo Transfer, Vetmeduni Vienna, Vienna, Austria.
authors.forename: Natascha
authors.initials: N
authors.lastname: Ille
authors.affiliation: Obstetrics, Gynecology and Andrology, Vetmeduni Vienna, Vienna, Austria.
authors.forename: Jörg E
authors.initials: JE
authors.lastname: Aurich
authors.affiliation: Artificial Insemination and Embryo Transfer, Vetmeduni Vienna, Vienna, Austria.
authors.forename: Christine
authors.initials: C
authors.lastname: Aurich
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D003008:Cloprostenol / Q000009:adverse effects / Q000494:pharmacology*; D015237:Dinoprost / Q000819:agonists*; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006736:Horses / Q000502:physiology; D008183:Luteal Phase / Q000187:drug effects / Q000502:physiology; D003341:Luteolysis / Q000187:drug effects*; D011461:Prostaglandins F, Synthetic / Q000009:adverse effects / Q000494:pharmacology*; D012881:Skin Temperature / Q000187:drug effects; D013312:Stress, Physiological / Q000187:drug effects
chemical_list: D011461:Prostaglandins F, Synthetic; D003008:Cloprostenol; D015237:Dinoprost; C049643:luprostenol
keywords: Analogs; Corpus luteum; Horse; Luteolysis; Mare; PGF(2α); Stress response