Diseases of the Endocrine Glands - Anterior pituitary gland
The anterior pituitary gland, also called the hypophysis , is located in the center of the brain. It produces two types of secretions: a growth hormone and hormones that stimulate certain other glands.
The anterior pituitary gland is subject to neurochemical stimulation by the hypothalamus , a nearby part of the brain. This stimulation results in the production of the hormones that promote testicular and ovarian functioning, and does not occur normally until around 12 years of age in girls and 14 in boys. The beginning of this glandular activity is known as the onset of puberty .
Puberty is sometimes delayed for no apparent reason until age 16 or 17. Because the hypothalamus is affected by emotional factors, all of the endocrine glands governed by the anterior pituitary can also be affected by feelings. Psychological factors can therefore upset the relationships in the glandular system and produce the physical symptoms of endocrine disorders.
It is extremely rare for the anterior pituitary to produce too much or too little of its hormones, but sometimes hypofunction may follow pregnancy because of thrombosis or changes in the blood vessels.
A truly hypofunctioning anterior pituitary gland can cause many serious disturbances: extreme thinness, growth failure, sexual aberration, and intolerance for normal variations in temperature. When appropriate diagnostic tests determine the deficiency, the patient is given the missing hormones in pill form.
Absence of the growth hormone alone is unknown. Most cases of dwarfism result from other causes. However, excess production of the growth hormone alone does occur, but only rarely. If it begins before puberty when the long bones are still growing, the child with the disorder will grow into a well-proportioned giant. When it begins after puberty, the head, hands, feet, and most body organs except the brain slowly enlarge. This condition is called acromegaly . The cause of both disorders is usually a tumor, and radiation is the usual treatment.
The thyroid, adrenal cortex, testicles, ovaries, and pancreatic glands are target glands for the anterior pituitary's stimulating hormones, which are specific for the functioning of each of these glands. Therefore, a disorder of any of the target organs could be caused either by an excess or a deficiency of a stimulating hormone, creating a so-called secondary disease . There are various tests that can be given to differentiate primary from secondary disorders.