ABSTRACT
Respiratory distress syndrome (RDS) is a major cause of death in premature neonates, and it is caused by the failure of morphological and biochemical lung maturation (synthesis and secretion of lung surfactant). It is known that cortisol, thyroxine, prolactin, epidermal growth factor (EGF), and estrogen accelerate the lung maturation. Cortisol and thyroxine are currently used in the antenatal treatment for the prevention of RDS in premature neonates. In order to evaluate the effect of EGF on the levels of cortsol, thyroxine, and prolactin, this study was undertaken. Phosphate buffered saline (PBS) with and without EGF was directly injected into the 25 days gestational fetus in uterus. Blood was collected for the measurement of cortisol, thyroxine, and prolactin one day or two days after the injection. Body weights and lung weights were also measured. The results were as follows: 1. There was no significant difference in body weights and lung weights between PBS-treated group(control group) and EGF-treated poup(experimental group), 24 hours and 48 hours after the injection. 2. 24 hours after the injection, the levels of cortisol were significantly inaeased in the EGF-treated group compared with those in the PBS-treated group. However 48 hours after the injection, there was no significant difference in the levels of cortisol between the two groups. The levels of thyroxine and prolactin in the EGF-treated group did not significantly differ from those in the PBS-treated group 24 hours and 48 hours after the injection. In conclusion, in vivo, the synthesis of cortisol may be affected by EGF treatment, which suggests that the action of EGF for lung maturation may be partially mediated by the increased endogenous levels of cortisol.