Glucocorticoid receptor concentrations in human lung at different growth stages

We measured glucocorticoid receptor concentrations in human lung at different stages of alveolar growth. Lung tissue was obtained from 9 surgically aborted or stillborn fetuses of 15 to 28 weeks gestational age, and from 6 infants and children, aged 2 months to 9 years, after lobar resection or at autopsy. Samples were taken from macroscopically healthy areas. Lung histology was performed in all cases. The receptor assay was done by establishing saturation curves for labeled dexamethasone in the absence or presence of a hundredfold excess of unlabeled dexamethasone. Total binding capacity and the dissociation constant were calculated from the saturation curves by the method of Scatchard. The receptor concentration in the fetuses was high (182 +/- 88 fmol/mg prot.), irrespective of gestational age. The lowest concentration (35 fmol/mg prot.) was found in a fetus with pulmonary hypoplasia. In the infants and children the mean receptor concentration was significantly lower (14.6 +/- 9.9 fmol/mg prot.); these included a case of sudden death in which the parenchymal structure was normal.