Answer:
(D). oxytocin.
Step-by-step explanation:
The hypothalamic-pituitary axis can be defined a pathway that plays a central role in regulation of various endocrine glands. Hormones released from hypothalamus stimulates pituitary gland, which in turns secrete pituitary hormones to regulate release of hormones from other endocrine glands.
Regulation of growth hormone (somatotropin), cortisol (adrenal hormone), prolactin, and T3 (thyroid hormone) is done by hypothalamic-pituitary axis.
Oxytocin is a peptide hormone, which is synthesized by hypothalamus and secreted by posterior pituitary gland. However, level of oxytocin is regulated by positive feedback in loop, in which hormone itself regulates its release and does not involves regulation by hypothalamic-pituitary axis.
Thus, the correct answer is option (D).