Hormones are the substances secreted by highly specialized cells and carried by the extra cellular fluid and act through the receptor on the target organ to alter the activity of the cells quantitatively to influence metabolism, growth, reproduction and adaptation to the environment. Steroids and peptides are the two types of hormones. Steroids are sex hormones related to sexual maturation and fertility. Peptides regulate sleep and sugar level. The pituitary hormones are of two types: anterior and posterior. Growth hormone, TSH, ACTH, FSH, LH and prolactin are the anterior pituitary hormones. Oxytocin and ADH are the posterior pituitary hormones. Thyroid gland secretes T3 and T4. Parathyroid secretes PTH. Mineralocorticoids, glucocorticoids and sex steroids are from adrenal gland. Insulin and glucagon are secreted from pancreas. Testes secrete testosterone and progesterone and estrogen are from ovary.