Changes in pulmonary structure and function induced by monocrotaline intoxication.

Monocrotaline, a pyrrolizidine alkaloid derived from Crotalaria spectabilis, is known to be toxic to a variety of domestic and laboratory animals and to humans. Major pathological effects induced by monocrotaline poisoning include hepatic cirrhosis and megalocytosis, venocclusive disease, pulmonary hypertension, and right ventricular hypertrophy. The present investigation explored the structural and functional relationships that exist between pulmonary artery pressure, small pulmonary artery medial thickness, and right ventricular hypertrophy. The results of this physiological and histological study on monocrotaline-intoxicated rats has demonstrated that there is a positive correlation between progressive pulmonary hypertension, thickening of the medical wall of small pulmonary vessels, and right ventricular hypertrophy as a function of time.