ADRENOCORTICAL FUNCTIONS DURING ANTIGEN-INDUCED LATE ASTHMATIC RESPONSES.

It is well-known that premedication of corticosteroids inhibits the development of late asthmatic responses (LAR) in allergen inhalation tests on asthmatics. This fact suggests that impaired functions in steroid synthesis or metabolism may play a role in the induction of LAR.In order to clarify these possibilities, the author performed allergen inhalation tests on asthmatic patients. Serial changes in their bronchial responses and plasma cortisol and ACTH levels were observed. Furthermore, to investigate regional level of cortisol in the lung, a new animal LAR model of ovalbumin sensitized guinea-pig was made. Following allergen inhalation tests, serial cortisol levels in serum and broncho-alveolar lavage fluid (BALF) were measured in this animal model for 24 hours.During LAR phase, blood cortisol levels were markedly decreased in both asthmatics and guinea-pigs with accompanying mirror image of the increase of BALF cortisol level. However, no change in serial plasma ACTH levels was noted.The results of the present study suggest that decreased serum cortisol levels are involved in the pathogenesis of antigen-induced LAR.