The present invention is directed to certain piperidines, pyrrolidines, and hexahydro-1H-azepines of the general structural formula: ##STR1## wherein B is selected from: ##STR2## and R.sup.1, R.sup.1a, R.sup.2a, R.sup.3a, R.sup.3b, R.sup.4, R.sup.4a, R.sup.4b, R.sup.4c, R.sup.5, D, X, Y, n, x and y are as defined herein. These compounds promote the release of growth hormone in humans and animals. This property can be utilized to promote the growth of food animals to render the production of edible meat products more efficient, and in humans, to treat physiological or medical conditions characterized by a deficiency in growth hormone secretion, such as short stature in growth hormone deficient children, and to treat medical conditions which are improved by the anabolic effects of growth hormone. Growth hormone releasing compositions containing such compounds as the active ingredient thereof are also disclosed.