Publisher Summary This chapter explains hexarelin, which is a synthetic growth hormone secretagogue that exhibits protectant activity in experimental myocardial ischemia and reperfusion. The first strong support to the rational use of growth hormone (GH) in cardiovascular diseases was due to the observation that administration to normal subjects induced positive inotropic effects. The present results indicate that hexarelin given to rats with selective GH deficiency is capable of restoring somatotropic function to an extent similar to that induced by GH replacement therapy. Aging has been shown to alter the spectrum of physiological and biochemical properties of the myocardium, including force production, excitation–contraction coupling, substrate use, and mitochondrial oxidative capacity. The findings clearly indicate that hexarelin, very likely through a mechanism divorced from its GH-releasing effect, strikingly reduces the reperfusion injury in isolated hearts from senescent rats. This action of hexarelin, which under the experimental conditions, opens new perspectives in the therapy of postischemic heart dysfunction in the elderly. This subject is of increasing interest because the aged population is continuously growing and is becoming one of the major targets of pharmacology. Moreover, cardiac diseases are the first cause of mortality after the age of 65 years.