Down regulation of hormone means ?
Decreased secretion of hormone
Decreased affinity to receptors
Defective regulation in secretion
Regulation by low concentration of hormone
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.