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Research article1991Peer reviewed

Clenbuterol plasma concentrations after repeated oral administration and its effects on cardio‐respiratory and blood lactate responses to exercise in healthy Standardbred horses

KALLINGS, P; INGVASTLARSSON, C; PERSSON, S; APPELGREN, LE; FORSTER, HJ; ROMINGER, KL

Abstract

To evaluate the effects of clenbuterol on cardio-respiratory parameters and blood lactate relation to exercise tolerance, experimental horses performed standardized exercise tests on a high-speed treadmill before and after administration of the drug. Clenbuterol was administered in feed to six healthy Standardbreds at a dose rate of 0.8-mu-g/kg b.wt twice daily for 5.5 days. Each horse was tested twice, without and with a respiratory mask, during two consecutive days. One week elapsed between the baseline tests without drug and the test with clenbuterol treatment (each horse served as its own control). The results show an unchanged heart rate response to exercise 2 h after the last clenbuterol administration. The blood lactate response and the arterial oxygen tension during exercise did not differ before and after drug treatment. The oxygen uptake as well as pulmonary ventilation relative to the work load performed was essentially unaffected. The arterial pH during exercise was significantly increased (P < 0.05) following clenbuterol treatment. Plasma levels of clenbuterol were maximal 2 h post-administration with values between 0.45 and 0.75 ng/ml. The plasma half-life of elimination was 10.4 h (+/- 2.25 SD). In conclusion, clenbuterol did not cause any major effects on the cardio-respiratory and blood lactate parameters studied in healthy horses performing submaximal exercise tolerance tests.

Published in

Journal of Veterinary Pharmacology and Therapeutics
1991, Volume: 14, number: 3, pages: 243-249
Publisher: BLACKWELL SCIENCE LTD

      SLU Authors

    • Kallings, Peter

      • Department of Medicine and Surgery, Swedish University of Agricultural Sciences

      • Ingvast Larsson, Carina

        • Department of Pharmacology and Toxicology, Swedish University of Agricultural Sciences

        • Appelgren, Lars-Erik

          • Department of Pharmacology and Toxicology, Swedish University of Agricultural Sciences

        UKÄ Subject classification

        Pathobiology

        Publication identifier

        DOI: https://doi.org/10.1111/j.1365-2885.1991.tb00833.x

        Permanent link to this page (URI)

        https://res.slu.se/id/publ/97425