This 55-year-old woman presented with primary adrenal insufficiency that led to multiple endocrine gland dysfunctions. Despite symptoms suggestive of hypothyroidism, she had mildly elevated serum thyroid hormone levels associated with elevated thyrotropin levels, hyperprolactinemia, and mild hypercalcemia. These abnormalities corrected with corticosteroid replacement but could be reproduced, in part, when the corticosteroids were temporarily withdrawn. The findings in this patient suggest that physiologic concentrations of glucocorticoids modulate prolactin secretion and the pituitary-thyroid axis. Adrenal insufficiency should be considered in the differential diagnosis of hyperprolactinemia and hyperthyrotropinemia with or without associated hyperthyroxinemia.