Acromegaly patients, who suffer from natural growth hormone levels of up to 100 times higher than normal, have lower stamina towards physical activity than people with regular levels.  When the patients are treated and their growth hormone levels decrease, their stamina improves.  This knowledge is part of the evidence behind the new belief that athletes who use supplemental HGH to raise their levels far above average could actually decrease their exercise tolerance, and thus hurt their athletic performance.  Further backing was provided in a study done by the Danish Institute of Sports Medicine. They found cyclists of good health and endurance “were unable to complete accustomed cycling tasks after administration of exogenous hGH” and concluded that HGH can inhibit recuperation from exercise.  Participants have also been found to have lower stamina after HGH treatment along with higher rates of fatigue. 
Third, GH may influence the activity of IGF-1 on an autocrine/paracrine level. Autocrine means that a hormone has an effect on the cell that produced it, paracrine means to have an effect on the “cell(s)” next to it as well. This is a completely localized effect, not dependent on the blood stream to carry things where you want them. Muscle growth from weight training is the result of IGF-1 being produced by the muscle cells themselves, not the liver. In fact, IGF-1 form the liver is genetically different from IGF-1 produced in your muscles. This information should explain why using IGF-1 systemically (from the blood stream) has been a hit and miss proposition.
Because steroids are lipophilic, they diffuse easily through the cell membranes, and therefore have a very large distribution volume. In their target tissues, steroids are concentrated by an uptake mechanism which relies on their binding to intracellular proteins (or " receptors ", see below). High concentration of steroids are also found in adipose tissue, although this is not a target for hormone action. In the human male, adipose tissue contains aromatase activity, and seems to be the main source of androgen-derived estrogens found in the circulation. But most of the peripheral metabolism occurs in the liver and to some extent in the kidneys, which are the major sites of hormone inactivation and elimination, or catabolism (see below).