Quiz 15: Drugs for the Endocrine System

Medicine

The seven major glands of the body are pituitary, thyroid, parathyroid, adrenal, pancreas, ovary and testes. The hormones secreted by them are listed below. The pituitary gland secretes growth hormone also called as somatotropin. The thyroid secretes thyroxine (also referred to as T4), triiodothyronine (also referred to as T3) and calcitonin. The parathyroid glands secrete parathyroid hormone. The adrenals secrete corticosteroids. The pancreas secretes insulin, glucagon and somatostatin. The ovary secretes estrogen and progesterone. The testes secrete testosterone.

The use of excessive oxytocin might lead to the development of condition known as uterine tetany. This is defined as a condition that is characterized by contractions in the uterus that lasts for a longer duration. The condition of imbalance in electrolytes might also lead to the development of tetany. It is found that tetany develops mostly due to low calcium, magnesium or potassium level. The presence of low level of calcium in the body is termed as hypocalcaemia. The presence of high level of acid or alkali in the body can also result in the development of tetany in the person. Even the presence of toxins in the body can cause the development of tetany in the person.

Hormones are enzymes secreted directly in the blood by specialized organs. The circulatory system carries these hormones to their respective target cells with which they react to give the desired effect. Somatotropin This is the hormone that controls overall growth of the body. Primarily it stimulates secretion of insulin-like growth factor (IGF-1) by different organs including the liver, metamorphosis and proliferation of myoblasts and protein synthesis in the muscle and other tissues. Thyroxine (T4) Thyroxine plays a crucial role in the regulation of metabolism, heart function, development of the brain and muscle control. Parathyroid hormone It helps in regulating the calcium levels. When the calcium levels become low, parathyroid releases calcium from the bones and increases the absorption of calcium from the intestines. Mineralocorticoids They regulate the blood volume, which in turn impacts the blood pressure. The regulation of blood volume is the result of increase in the sodium re-absorption by an action on the tubules of the kidney due to which more water is retaining more water in the body and thereby increasing the blood volume. Aldosterone and deoxycorticosterone are mineralocorticoids. Glucocorticoids Glucocorticoids impact the carbohydrate metabolism by stimulating proteolysis and lipolysis and decreasing the glucose utilization or increasing the glucose production by the liver. Epinephrine Epinephrine is a sympathomimetic agent that relaxes the airways and causes vasoconstriction. The drug is of particular use in bronchial asthma. Norepinephrine Norepinephrine is only alpha receptor agonist and alpha receptors are there only on arteries. It is used in conditions where rapid increase in blood pressure is required such as in the case of shock. Norepinephrine helps by causing vasoconstriction. Insulin Insulin regulates the sugar in the body by enhancing the absorption of glucose by the muscles and fat tissues. It also induces glycogen synthesis by inhibiting the enzyme glucose-6-phosphatase and activating hexokinase, phosphofructokinase and glycogen synthase. Adrenocorticotropic hormone The adrenocorticotropic hormone binds to receptors on adrenal glands and increases the secretion of cortisol. Antidiuretic hormone (ADH) It causes reabsorption of water into the blood, thereby reducing the viscosity and osmolarity of blood and increasing the osmolarity of urine. This mechanism reduces the loss of water from the body.