<prompt> Down regulation of hormone means ?Decreased secretion of hormoneDecreased affinity to receptorsDefective regulation in secretionRegulation by low concentration of hormone  <response>: Ans. is b i.e., Decreased affinity to receptors Down regulation is a mechanism in which a hormone decrease the number or affinity of its receptors in target tissues. Down-regulation may occur by decreasing the synthesis of new receptors, by increasing the degradation of existing receptors or by inactivating receptors. The purpose of down-regulation is to reduce the sensitivity of the target tissue when hormone levels are high for an extended period of time. 