GCG and Insulin resistance: GIP was higher during the IIGI than during fasting and lower during the OGTT.(11) As mentioned earlier, octreotide, which inhibits incretins, negates the effects of the OGTT on bone turnover markers.(10) A mixed meal test suppresses CTX by more than that observed during the OGTT.(9) The suppression of P1NP is inversely dependent on insulin resistance, though this does not seem to be the case for CTX.(9) Likewise, fasting P1NP seems to be inversely dependent on insulin resistance.(9)