The effects of sustained delivery of corticosterone on the adrenal gland of male and female rats - biomed 2013.

Glucocorticoids have long been recognized to have beneficial effects in rheumatoid arthritis and asthma. Numerous clinical trials show the efficacy of short term low dose treatment to resolve inflammation. Despite the success of short term use, there is concern regarding chronic use of glucocorticoids because of the development of exogenous Cushing’s syndrome. Chronic variable stress models have detailed the effects of chronic stress exposure on body weight, plasma corticosteroid levels, ACTH levels, and adrenal weights, but limited studies detail the effects of the body systems induced by continuous exposure to glucocorticoids similar to that seen in exogenous Cushing’s syndrome. The present study uses a TCPL drug delivery system to administer corticosterone (CS) continuously in male and female animals for 24 days and evaluates long term chronic use effects on body weight, adrenal weight, and adrenal ultrastructure. Continuous release of CS resulted in slight decreases in body weight in both male and female rats and decreases in adrenal wet weight in the female rats. Ultrastructural changes were seen in the adrenal histology in both female and male rats. Male rat adrenal glands showed atrophy of the zona glomerulosa and hypertrophy of the adrenal medulla. Female rats showed disorganization of all zones within the adrenal gland and an increase in fat around the gland. The information is important for understanding physiological differences in males and females during stress. The continuous release of CS may provide insight into the pathology of exogenous Cushing’s syndrome.