You are examining the responses of adipocytes in culture to the addition of various peptide hormones. You find that after the addition of one hormone in your study there is an increase in glucose uptake from the media. Which of the following is the most likely initial event triggered by the addition of the test hormone, leading to the observed effects?
A) activation of adenylate cyclase by the receptor
B) autophosphorylation of threonine residues in the receptor
C) interaction of the receptor with a signal cascade protein
D) interaction of the receptor with the glucose transporter
E) translocation of the hormone receptor complex to the nucleus

Question

Quizplus · Accepted Answer

The test hormone in this study is most likely to be insulin. All of the postreceptor responses initiated by insulin binding to its receptor are mediated as a consequence of the activation of several signal transduction pathways. One of the responses of adipocytes to insulin is the association of GRB2 with IRS1. This association activates GRB2 which in turn activates the G-protein, RAS.

You Are Examining the Responses of Adipocytes in Culture to the Addition