F. Moutaouakil and M. Bengoumi
Laboratoire de Biochimie Clinique et Nutritonnelle, Département de Pharmacie,
Toxicologie et Biochimie, I.A.V. Hassan II, BP 6202 Rabat-Instituts, Maroc
ABSTRACT
Osmolality, plasma triiodothyronine (T3) and thyroxine (T4) were determined by freezing point, microparticular enzymatic immunoassay (MEIA) and fluorescence polarisation immunoassay (FPIA), respectively, in male dromedary camels (n = 5), 3-5 years old, weighing 275 ± 15 kg (mean ± SEM), before and after 4 km of racing (15 min, 3, 6, 12 and 24 hours) at maximum speed (6.3 m/s = 22.6 km/h ), before feeding in the morning, when the ambient temperature was approximately 25°C. There were significant increase in osmolality (p<0.05), plasma T3 (p<0.01) and T4 (p<0.01), and T3/T4 ratio (p<0.05). Osmolality returned to pre-exercise levels within 3 h of completion, T3/T4 ratio in 6h, T3 and T4, 24 h post-exercise. The different evolution of these parameters suggested that the maximal exercise act on thyroid hormones not through plasmatic volume variations, but directly on their activities pathways (secretion, mobilisation and metabolism).
Key words : Camel, maximal exercise, osmolality, thyroxine, triiodothyronine