an endocrine gland adjacent to the kidney. Its outer layer, the adrenal cortex, secretes such hormones as androgens, glucocorticoids, and mineralocorticoids. Its inner core, the adrenal medulla, secretes the hormones epinephrine and norepinephrine, both of which are catecholamines and also serve as neurotransmitters. Also called suprarenal gland.