The effect of glycogen depletion and lactate clamp on serum CGRP response to endurance training

The effect of glycogen depletion on CGRP response to endurance training and possible role of lactate on resting CGRP release were investigated in the present study. Ten active men with age 22. 4 ± 1. 67، weight 71. 28 ± 5. 56 and BMI 23. 31 ±1. 07 were participated in the study. In four separated sessions with at least one week wash out time between them، Each subject performed the Pmax test، acute time trial endurance exercise (control test)، acute time trial endurance exercise after glycogen depletion (depletion test) and lactate clamp test. The blood samples were collected before and immediately after each test in order to determination of plasma lactate، serum CGRP and triglyceride concentrations. Plasma lactate and serum CGRP concentration were determined by RIA and ELISA techniques، respectively. The differences of variables between depletion and control tests were determined by one-paired sample t test. Serum CGRP concentration was significantly increased from its baseline values in control (P<0. 001)، depletion (P<0. 001)، and lactate clam tests (P<0. 001). In addition، significant difference was found on post exercise value of serum CGRP concentration between control and depletion tests (P<0. 01). There was a significant relationship between the levels of plasma lactate and serum CGRP concentration (P<0. 01). Immediately after exercise، serum triglyceride concentration was significantly different between control and depletion tests (P<0. 01). In summary our results shown that acute endurance exercise increase CGRP concentration and it likely incorporates in fat oxidation pathways. Also، regarding to the result of lactate clamp test، increase in serum CGRP concentration can be attributed to elevation of blood lactate concentration.