Final answer:
The substance that performs most of the actions of growth hormone (GH) directly on the body is Somatomedin or insulin-like growth factors (IGFs). GH stimulates the liver to produce somatomedins, which are growth-promoting proteins.
Step-by-step explanation:
The substance that performs most of the actions of growth hormone (GH) directly on the body is Somatomedin or insulin-like growth factors (IGFs)GH stimulates the liver to produce somatomedins, which are growth-promoting proteins. These somatomedins then stimulate tissue growth and play a major role in the growth-promoting effects of GH