(5) Luteinizing hormone (LH). LH promotes the maturation of the ovarian
follicle; secretion of progesterone; ovarian follicle to release the ovum; and the
conversion of the ruptured follicle into the corpus luteum (the scar tissue which forms
the ruptured follicle).
(6) Pituitary growth hormone (PGH). PGH is a growth hormone. Also
known as the somatotropic hormone (STH), this hormone turns on body cells to grow.
The principal function is to increase the rate of growth of body cells and to maintain their
size once growth is attained. The growth hormone also increases the rate of protein
synthesis and promotes a process called fat catabolism. Fat catabolism causes cells to
switch from burning carbohydrates to burning fats for energy.
c. Posterior Lobe--Hormones.
(1) Antidiuretic hormone (ADH). This hormone has a potent antidiuretic
action. ADH makes the collecting duct of the kidney permeable to water and allows
reabsorption of water and concentration of urine in the kidney.
(2) Oxytocin. Oxytocin is formed in the base of the brain (hypothalamus)
and stored in the posterior lobe of the pituitary gland. This hormone stimulates smooth
muscle and causes strong contractions of the uterus and the ejection of milk from the
Oxytocin is not to be confused with the hormone prolactin which stimulates
the production of milk.
a. Description. The thyroid gland is located just below the larynx with a right
and left lateral lobe on either side of the trachea. A mass of tissue called an isthmus
lies in front of the trachea and connects the two lateral lobes of the thyroid gland. The
thyroid gland weighs about 25 grams and receives a rich supply of blood (about 80 to
120 ml per minute).
b. Hormones. Thyroid hormones have three principal effects on the body.
They regulate the body's metabolism rate; regulate the body's growth and development;
and regulate the activity of the nervous system. To fulfill these functions, the thyroid
gland releases these hormones; tetraiodothyronine (thyroxine or T4) and
triiodothyronine (T3). Both of these hormones contain iodine. Iodine collects in the
thyroid gland in the process of thyroid hormones being made.