The impact of blood glucose levels on stimulated adrenocorticotropin hormone and growth hormone release in healthy subjects.

Objective: In studies investigating the influence of glucose levels on the pituitary function the methods used have been variable and mainly focused on the change in function as a reaction to unphysiological low or high blood glucose levels. In the present study the impact of physiological and elevated blood glucose levels on adrenocorticotropin hormone (ACTH) and growth hormone release are investigated.

Design: The euglycaemic and hyperglycaemic clamp techniques were used to reach stable levels of 4, 8 and 12 mmol/l blood glucose levels. After a stabilization phase of 2 h, a corticotropin releasing hormone (CRH) or a growth hormone releasing hormone (GHRH) stimulation test was performed.

Subjects: Seven and eight healthy male volunteers, belonging to two groups, participated in this study.

Measurements: The area under the curve (AUC), peak values and time to peak of ACTH, cortisol and growth hormone were calculated to evaluate the response to the CRH and GHRH stimulation test.

Results: The peak values of ACTH, cortisol and growth hormone seemed to be the highest during the 4 mmol/l clamp sessions, compared with the 8 and 12 mmol/l clamps, although the differences were not statistically significant when analysed for every subject individually. The AUC and time to peak measurements were comparable during the three clamp procedures.

Conclusion: The pituitary reaction on CRH and GHRH was not significantly changed by various blood glucose levels.