Somatotrope
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Somatotropes are cells in the anterior pituitary which produce growth hormone. These cells constitute 30-40% of anterior pituitary cells. They respond by releasing HGH in response to GHRH (somatocrinin) or are inhibited by GHIH (somatostatin), both received from the hypothalamus via the hypophyseal portal system vein and the secondary plexus.
Somatotrope cells are classified as acidophilic cells. These cells take years to grow and mature very slowly. If these cells grow large enough they can impair vision, cause headaches or damage other pituitary functions.
These cells produce Growth Hormone in response to Growth hormone releasing hormone. If there is an excess of growth hormone it is usually because of over secretion of somatotrope cells in the anterior pituitary gland. This is what happens if you have a disease known as gigantism.
Bovine somatotropin occurs in the pituitary of cattle and differs in structure from human pituitary growth hormone and is biologically inactive in the human being. Bovine somatotropin aids in regulating the amount of milk produced. rbST is a hormone that is injected in cows that increases milk production.
When levels of somatotropin are low in the body it is possible to take a supplement known as Protropin. This is a man-made growth hormone that can be given to children who have diseases, or naturally occurring problems that limit the amount of hormone being produced. Examples of these diseases are human growth hormone deficiency, kidney’s disease, Turner’s syndrome or Prader-Willi Syndrome (PWS). It is also possible to be used in adults who are coping with weight loss from acquired immunodeficiency syndrome (AIDS). Protropin is illegal when used for athletic purposes.
Deficiency in somatotrope secretion before puberty, or before the end of new bone tissue growth, can lead to pituitary dwarfism. When growth hormone is deficient blood sugar is low because insulin is not opposed by normal amount of growth hormone. This can lead to diabetes in dwarfs. Dwarfs are usually well proportioned, but sometimes have a large head compared to the body. Treatment includes injections of somatotrope.
A significant amount of excess somatotrope secretion before puberty, or before the end of new bone tissue growth, can lead to gigantism. Gigantism is a disease that causes excess growth of body (eg. being over 7 ft. tall) and unusually long limbs. An excess of secretion of growth hormone after puberty can lead to acromegaly. This is a disease that causes abnormal growth in the hands, head, jaw, and tongue. Some symptoms associated with acromegaly include heavy sweating, oily skin, improper processing of sugars in the diet (diabetes), high blood pressure, increased calcium in urine and swelling of the thyroid gland and arthritis.
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