BIOM 3200 Lecture Notes - Lecture 3: Growth Hormone Treatment, Collagen, Ghrelin
4 Feb 2017
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Document Summary
Most abundant anterior pituitary hormone (10 times more) Synthesized, stored and secreted by somatotropic cells in the lateral wings of anterior pituitary gland. Occurs as several large pulse/peeks each day: 10-30 min in duration largest peak ~1 hr after onset of sleep (circadian) Basal levels are highest during puberty growth spurt and gradually decline through adult life. Cartilage (ears) continue to grow and are not influenced by gh. Transport transported as free hormone but much of it is bound to binding protein (ghbp) Gh acts on the liver to produce igfs. Insulin-like growth factors (somatomedins): igf-1, igf-2: polypeptides with 40% homology to insulin. Igf-1 is almost entirely bound to transport proteins (igf-bps) Some of the transport/binding proteins of igf-1 have an endocrine function: there are receptors for these proteins. Gh stimulates synthesis and release of igf-1 in many tissues not just the liver. Hard to differentiate between the direct action of gh and those of igf-1.
