Reduction of Lung Distensibility in Acromegaly after Suppression of Growth Hormone Hypersecretion

Whether the growth of the lungs in acromegaly is due to alveolar hypertrophy or alveolar hyperplasia is a subject of debate. To discriminate these hypotheses, we compared pulmonary distensibility and diffusing capacity among 11 patients with active acromegaly and 11 matched control subjects, evaluating the response of pulmonary distensibility and diffusing capacity to suppression of growth hormone (GH) hypersecretion. We performed lineal and exponential analyses of quasistatic pressure–volume curves. Patients with active acromegaly had a greater TLC, lung compliance, and shape constant, K, than did normal subjects. We found no significant differences between the study groups in carbon monoxide diffusing capacity or diffusing capacity per unit of alveolar volume. After treatment, patients with inactive acromegaly showed a reduced TLC (6.95 ± 1.40 [mean ± SD] L versus 6.35 ± 1.23 L), reduced lung compliance (3.61 ± 0.90 L/kPa versus 2.36 ± 0.79 L/ kPa), reduced K coefficient (2.62 ± 0.65 kPa− 1 versus 1.35 ...