Types of hormones -
(i) Releasing and Inhibitory hormones - Hormones of hypothalamus and kidney (renin) which control secretion of trophic hormones.
(ii) Trophic hormones - Hormones controlling activity of other endocrine glands and growth, e.g. anterior pituitary hormones like thyrotropin for thyroid.
(iii) Hormones connected with Reproduction. FSH, LH (ICSH), oxytocin are sex hormones. (iv) Hormones connected with Growth and Development. GH (somtotrophin), thyroxine.
(v) Hormones of Digestive system. Gastrin, secretin, enterocrinin etc.
(vi) Hormones connected with Metabolism. Insulin glucagon, calcitonin, corticoids
(vii) Hormone Neurotransmitters. Hormones which also function as neurotransmitters, e.g., noradrenaline (= nore- pinephrine), adrenaline (=epinephrine).