<P> Hormone receptors are dynamic structures . Changes in number and sensitivity of hormone receptors may occur in response to high or low levels of stimulating hormones . </P> <P> Blood levels of hormones reflect a balance between secretion and degradation / excretion . The liver and kidneys are the major organs that degrade hormones; breakdown products are excreted in urine and feces . </P> <P> Hormone half - life and duration of activity are limited and vary from hormone to hormone . </P> <P> Permissiveness is the situation in which a hormone cannot exert its full effects without the presence of another hormone . </P>

Endocrine glands in human beings and their functions