Hormonal Control of Compensatory Lung Growth

In a variety of mammalian species, partial resection of the lung results in rapid compensatory growth of the remaining lobes to restore normal total lung mass, volume, and function. Although this phenomenon was first described more than 100 years ago (1), it was the classic studies of Cohn in 1939 (2) which stimulated investigations of the mechanisms by which compensatory lung growth is initiated and controlled. Numerous laboratories have contributed to the latter work in providing a description of the general characteristics of compensatory growth, of the time course over which it occurs, and of the resulting changes in tissue structure and function. These results show that the detailed aspects of compensatory lung growth reflect not only the species in which the surgery is performed but also the age, sex, and hormonal status of the animal. Several investigators have previously reviewed the considerable body of data which describes the compensatory growth response (3-6). In spite of this extensive descriptive information, regulation of the response at both the cellular and subcellular levels remains poorly understood (7), and almost no information is available concerning the impact which lung injury may have on compensatory growth of the organ.