(i) Insulin hormone is secreted by pancreatic islets. Insulin increases the utilization of glucose in tissues and facilitates the storage of glucose as glycogen in muscles and liver. By these actions insulin lowers the blood sugar level. 

(ii) It is fact that Hypothalamus and Pituitary function as an integrated coordinated system. In hypothalamus, the hormones are synthesized in the neurosecretory cells body and then transported along the axon to its tip where the hormones are stored in droplets. Hypothalamic neuro-secreting cells secrete several hormones called neurohormones into this blood. These reach the anterior pituitary through the portal blood and control the secretion of hormones by the cells of that gland.

For example : Thyrotropin releasing hormone, corticotropin releasing hormone and gonadotropin releasing hormone of hypothalamus stimulates the anterior pituitary to secrete the hormones called thyrotropin, corticotropin and gonadotropins respectively. On the other hand the hormone somatostatin of the hypothalamus inhibits the secretion of growth hormone (GH) from the anterior pituitary. 

(iii) Sex hormones are secreted near the age of puberty or sexual maturity. Testosterone stimulates the development of the external male sex characters such as beards, moustaches, and low pitch male voice in man. Thus, testosterone promotes the growth of many body tissues including bones and muscles. Androgens are such substances which stimulate the development of male sex characters.