Acupuncture and Hormone Balance
Chapter 11. Growth Hormone and Aging
Growth hormone is a protein of about 190 amino acids that is synthesized and secreted by cells called somatotrophs in the anterior part of the pituitary gland. It is a major participant in the control of several complex physiologic processes, including growth and metabolism.
Functions of Growth Hormone
1. Growth hormone simultaneously stimulates cartilage cells to differentiate and the liver and other tissues to produce a chemical called insulin-like growth factor-I, which leads to the proliferation of cartilage cells. When more cartilage cells are produced in the long bones, children will grow taller. However, growth is a very complicated process and requires the coordinated actions of several hormones. As a result, children sometimes do not grow much even after an injection of growth hormones. In adults, bones can no longer grow longitudinally; if there is too much growth hormone, the bones, nose, and extremities become thicker instead.
2. Growth hormone enhances the utilization of fat by stimulating triglyceride breakdown and oxidation in fat cells. It also suppresses the fat cells’ ability to take up and to accumulate circulating lipids.
3. Growth hormone helps maintain the blood glucose level. Insulin lowers blood sugar level by stimulating the uptake of glucose in the peripheral tissues. Growth hormone can suppress the activity of insulin and enhance the release of glucose into the blood from the liver. Paradoxically, the administration of growth hormone also stimulates insulin secretion, leading to hyperinsulinemia (too much insulin in the blood). When there is too much growth hormone, the blood sugar level can rise even though insulin secretion increases because the function of insulin is suppressed by growth hormone. This combination of high insulin and high blood sugar can lead to many kinds of inflammation.
4. Growth hormone increase bone density.
5. Growth hormone activates a gene critical for the body’s tissues to heal and regenerate, according to Robert Costa, a professor of biochemistry and molecular genetics at the University of Illinois at Chicago. Once this particular gene is turned on, cells proliferate and mature at a much faster pace. When scientists disabled this gene (Foxm1b) in mice, the repair of tissue damage became impaired...
© 2008 Li Zheng