Final answer:
IGF-1, or somatomedin, is a hormone produced in response to GH that promotes tissue growth by increasing amino acid uptake and protein synthesis in muscle, cartilage, and bone cells. It also plays roles in metabolism, such as breaking down triglycerides for energy and stimulating glycogen breakdown in the liver. IGF-1 thus integrally supports both growth and metabolic regulation.
Step-by-step explanation:
Insulin-like Growth Factor 1 (IGF-1)/Somatomedin Mechanism of Action
The mechanism of action of Insulin-like Growth Factor 1 (IGF-1), also known as somatomedin, is a critical aspect of how growth hormone (GH) mediates its effects on bodily growth and protein synthesis. IGF-1 is a hormone produced primarily in the liver, and its secretion is stimulated by GH. Once IGF-1 is in the bloodstream, it binds to its receptors on target cells, particularly skeletal muscle cells, cartilage cells, and bone, promoting the uptake of amino acids from the blood. This uptake facilitates the synthesis of new proteins and supports tissue growth. IGF-1 also has a vital role in cell proliferation and inhibiting apoptosis, thus contributing to cell survival and an increase in body size.
Furthermore, the actions of IGF-1 are not just limited to muscle and bone. It can also trigger the breakdown of triglycerides by adipocytes, releasing fatty acids into the blood, providing energy and sparing glucose. In the liver, IGF-1 stimulates the breakdown of glycogen, releasing glucose into the bloodstream, which can have a diabetogenic effect, raising blood glucose levels. Thus, the actions of IGF-1 are manifold, affecting various metabolic processes and overall growth patterns in the body, playing a vital role in developmental and metabolic homeostasis.