Urinary Excretion of Catecholamines and Vanilmandelic Acid in Rats Exposed to Cold

Male Sprague Dawley rats of an average weight of 300 g excreted during laboratory conditions at 20–22o C on an average 18 ng/kg/hr adrenaline (A), 97 ng/kg/hr noradrenaline (NA) and about 4 /ig/kg/hr vanilmandelic acid (VMA). Individual, diurnal and seasonal variations were noticed. During exposure to a temperature of +3o C, NA increased to 300– 400 ng/kg/hr in the first 24 hrs and remained high for the entire duration of exposure, while adrenaline excretion increased gradually to about 50 ng/kg/hr. The VMA excretion increased to about 10 jug/kg/hr during exposure to +3o C. After bringing the rats back to room temperature catecholamines and VMA excretion reverted to normal values in 1–2 days.