IGF -I plasma concentrations in non-treated horses and horses administered with methionyl equine somatotropin.
Insulin-like growth factor-I (IGF -I) is likely to be an indicator of somatotropin (ST) administration in the horse. To investigate the different ways ST administration may be detected, the following aspects of IGF -I concentrations in plasma were studied: (i) the daily variation; (ii) variation following a treadmill test; (iii) concentrations at rest and after exercise; and (iv) concentrations in plasma from two young horses and two adults treated with methionyl equine somatotropin (e ST). In the population of horses at rest, IGF -I mean concentration (SEM) was 261 (104) ng ml(-1). In post race samples, IGF -I mean concentration was 187 (100) ng ml(-1). All of these data indicate that exercise does not modify IGF -I concentration in plasma. The magnitude of the increase in IGF -I following administration of e ST differed according to the age of the horses. The critical value of 700 ng ml(-1)was exceeded for 1 day in adult horses and for at least 11 days in young horses. These results show that IGF -I has potential as an indirect marker of ST administration in horses.
Popot
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LAB/FNCF, 169 Avenue de la Division Leclerc, Châtenay-Malabry 92290, France. mariepopot@wanadoo.fr
Bobin
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Bonnaire
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Delahaut
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Closset
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D000367:Age Factors; D000818:Animals; D015415:Biomarkers / Q000032:analysis; D002940:Circadian Rhythm / Q000502:physiology; D004300:Doping in Sports; D005080:Exercise Test / Q000662:veterinary; D005260:Female; D013006:Growth Hormone / Q000008:administration & dosage* / Q000097:blood; D006736:Horses / Q000097:blood*; D007334:Insulin-Like Growth Factor I / Q000032:analysis* / Q000378:metabolism; D007601:Jugular Veins; D008297:Male; D010805:Physical Conditioning, Animal / Q000502:physiology; D012016:Reference Values; D012146:Rest / Q000502:physiology
D015415:Biomarkers; D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone