AbstractThe time response pattern of nicotine and the nicotine analogue 3‐pyrrolidino‐methylpyridine (W‐16) on the noradrenaline (NA) content of heart, spleen, kidney and liver was studied following intraperitoneal administration in rats. It was found that both compounds produced a transient but significant decrease. Nicotine produced an effect that was visible within 5 min with the NA content returning to control levels in 60–180 min. Although quantitatively different, W‐16 produced an effect qualitatively similar to nicotine. The effect of nicotine and several nicotine analogues on the 24‐hour urinary excretion of catecholamines was also studied in rats. Three out of four analogues investigated produced a slight increase in the excretion of adrenaline (A) and NA at high dose levels (5–10 mg/kg). At a dose of 1 mg/kg, nicotine produced a significant increase in the 24 hour urinary excretion of