Hormones are secreted by the endocrine glands and reach their targets after circulating in the blood. Many studies have documented that erythrocytes can bind hormones, and possible interactions have been reported. Erythrocytes are responsive to signaling initiated after binding of epinephrine, norepinephrine, estrogen, progesterone, thyroid hormones, parathyroid hormone, and angiotensin. Signaling results in regulation of cellular metabolism and membrane fluidity. In addition, erythrocytes are circulating pools for dopamine, thyroid hormones, cortisol, and aldosterone. Erythrocyte function and structure are regulated by endocrine signals, while erythrocytes are important constituents for the transport of hormones in the body.