The human growth hormone, released by the
anterior lobe of the
pituitary gland. The physiological
effects of this hormone are numerous. They are
associated with bone growth and cartilage extension; with the release of stored body fat and its
conversion to energy; with
increased protein absorption by
muscle cells (thus muscle
development and growth); and with accelerated use of the body's glucose (sugar). The hormone itself is
inextricably linked with the
release and the effect of thyroid, adrenal, and sex hormones.
When
pituitary disease or damage has occurred and somatotropin is deficient, growth is defective. Children born with a pituitary defect may grow very slowly (
pituitary dwarfs), but if the
condition is recognized early enough, treatment with the
hormone will permit them to reach a normal height. Excess growth hormone
production during childhood causes
gigantism. Excess growth hormone
secretion caused by a
tumor in later life
produces acromegaly; the condition can often be cured by treatment of the
pituitary tumor, either surgically or by radiation therapy.