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A number of puppies of the School Hospital of the Faculty of Veterinary Science-UBA showed bone changes. Measurement of the iodine content of the commercial diet showed a significant increase in its content. Iodine excess causes alterations in thyroid function and morphology, and its hormones have a direct action on bone formation. Three groups of puppies were fed on different diets: a home-prepared diet, a commercial diet (containing 5.6 mg potassium iodide/kg dry food), and a home-prepared diet supplemented with 5.6 mg potassium iodide/kg dry food. Groups B and C developed hypothyroidism. A significant decrease (p<0.05) in the styloid apophyseal surface was found in groups B and C vs. A, determined by radiography. Histologically, the hypertrophied cartilage was shorter in groups B and C than in group A (p<0.0001). The present results suggest that commercial diets with a high iodine content may cause hypothyroidism and changes in bone metabolism.

The procedure described here offers a sensitive and practical experimental model for the study of the pathogenesis of enteque seco.

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Glucose homeostasis is maintained by complex neuroendocrine control mechanisms. Increases in plasma concentrations of various glucose-raising hormones such as glucagon, catecholamines, adrenocorticotrophic hormone (ACTH), and cortisol are observed under certain conditions associated with stress (haemorrhage and hypoglycaemiaAccepted for publication 16th July, 1993. P < 0.01). In addition, decreased epinephrine (220 + 27 vs 332 + 32 pg" ml-l), and cortisol (4.48 q-0.3 vs 6.25 • ~tg. ml -I) concentrations were detected 60 min after insulin injection (P < 0.01). The norepinephrine response to hypoglycaemia was not altered by anaesthesia (273 + 33 vs 325 q-25 pg" ml-l). Anaesthetized dogs showed a decreased cortisol response to ACTH at 45 rain (5.68 • 0.54 vs 8.87 + 0.47 i~g' ml -t) when compared with control dogs (P < 0.001). Haemodynamic variables during anaesthesia showed little changes (P < NS