How might behaviors affect hormones? The birdsong example demonstrates how hormones can affect behavior, but as noted, the reciprocal relation also occurs; that is, behavior can affect hormone concentrations. For example, the sight of a territorial intruder may elevate blood testosterone concentrations in resident male birds and thereby stimulate singing or fighting behavior. Similarly, male mice or rhesus monkeys that lose a fight decrease circulating testosterone concentrations for several days or even weeks afterward. Comparable results have also been reported in humans. Testosterone concentrations are affected not only in humans involved in physical combat, but also in those involved in simulated battles. For example, testosterone concentrations were elevated in winners and reduced in losers of regional chess tournaments.
Cholesterol - Cholesterol is a major precursor of cholesterol ester, bile acids, and steroid hormones and is a component of plasma membranes. It is a necessary component of all cell membranes. It is the precursor to all steroid hormone (including estrogen , testosterone , cortisol , and vitamin D ). It is the leading organic molecule in the brain and is needed for brain function. However, too much cholesterol in the bloodstream can be unhealthy, it builds up in the artery wall and can lead to the signs and symptoms of coronary heart disease.