Endocrine Abstracts

Objective

It has been suggested that ghrelin may play a role in regulating the growth hormone (GH) response to exercise. This study was designed to determine whether very intense exercise alters circulating ghrelin concentrations. Design: Following Local Ethics Committee approval, 7 male volunteers were familiarised before completing two trials in a random order. In one trial participants performed a single 30-s sprint on a cycle ergometer, in the other they rested in the laboratory. Blood samples were taken pre-, immediately post-, 10 and 30 min post-exercise, and at equivalent time- points in the rest trial. Hormone data were corrected for changes in plasma volume. Results: Blood lactate concentrations increased approximately 14-fold following exercise, indicating that the exercise was demanding. Serum GH increased following exercise, and was significantly higher than pre-exercise 30 min after the sprint. Serum ghrelin decreased following exercise and was significantly lower than pre-exercise, and the corresponding time-points in the rest trial, 10 and 30 min after the sprint. There were no significant changes in GH, ghrelin or lactate in the rest trial, Table 1.>

Table 1 Mean(SD) serum GH and ghrelin at rest and following exercise (ex)

*significantly different from pre-exercise, p<0.05

# significantly different from corresponding time-point in rest trial, p<0.01

Conclusion

Circulating ghrelin is suppressed following very intense exercise, indicating that systemic ghrelin is unlikely to be responsible for exercise-induced GH release.