Cold-induced changes in circulating levels of catecholamines and thyroid hormones are modulated by energy intake in...

Newborn pigs were kept at a low ambient temperature from 6 until 54 h of age and supplied with a limited (LI, 415 g (kg body weight)-1) or a high (HI, 655 g (kg body weight)-1) intake of milk. At the end of the treatment, both groups had similar deep body temperatures and metabolic rates. However, plasma adrenaline and noradrenaline levels were, respectively, 5.8- and 3.0-fold lower (P < 0.01) in HI than LI piglets, whereas plasma 3,5,3'-triiodothyronine (T3) was 1.5-fold higher (P < 0.01) in HI piglets. It is concluded that the hormonal control of cold-induced thermogenesis is modulated by energy intake, with catecholamines and thyroid hormones acting in a closely related and complementary manner.