<prompt> Down-regulation isIncreased destruction of a hormoneFeed back inhibition of hormone secretionDecreased concentration of a hormone in bloodDecrease in number of receptors for a hormone  <response>: Downregulation: An decrease in the number of receptors on the surface of target cells, making the cells less sensitive to a hormone or another agent Downregulation of receptors happens when receptors have been chronically exposed to an excessive amount of hormone Ref : Biochemistry by U. Satyanarayana 3rd edition Pgno : 428 