good read bump on this: Human Growth Hormone also has the ability to stimulate the production (or reproduction, in the case of an injury) of cartilage. This, however, requires the presence of a mediator substance, Somatomedin (IGF), which is released from the liver in response to Human Growth Hormone, and the IGF, in turn, actually promotes the growth of cartilage.(1)
Although Human Growth Hormone requires IGF to actually grow new cartilage, Human Growth Hormone is directly able to stimulate the elongation of bone tissue.(1), and Human Growth Hormone has also been shown to elicit a positive effects on erythropoeisis (9), which is great for both anabolism as well as endurance.