The physiological distribution of intramuscularly and intravenously injected C
14-amitriptyline was studied in mice using an autoradiographic technique. The compound rapidly leaves the blood and concentrates in the brain, lung and heart. High concentrations are also seen in the gastric mucosa, intestines, salivary glands and lachrymal glands.
The compound is rapidly metabolized in the body. The excretion studies indicate that amitriptyline is excreted to a large extent into the bile as a glucuronide conjugate.
The significance of the tissue distribution in relation to the main pharmacological action and to some of the side effects are discussed.
The authors are indebted to Professor J. Rieder, Fa. Hoffmann-La Roche & Co., Basel, Switzerland for his helpful suggestions. Thanks are due to Mrs. G. Mabo, Mr. A. Nilsson and Mrs. B. Hagtorn for their valuable technical assistance. The authors are also indebted to Knut and Alice Wallenbergs Stiftelse for general equipment for isotope research work.