Paradoxical GH increase after oral glucose load in subjects with and without acromegaly

ObjectiveA paradoxical GH rise after the glucose load (GH-Par) is described in about one-third of acromegalic patients. Here, we evaluated the GH profile in subjects with and without acromegaly aiming to refine the definition of GH-Par.DesignObservational case-control study.MethodsOur cohort consisted of 60 acromegalic patients, and two groups of subjects presenting suppressed GH (< 0.4 & mu;g/L) and high (non-acro(& UARR;IGF-1), n = 116) or normal IGF-1 levels (non-acro, n = 55). The distribution of GH peaks & GE; 120% from baseline, insulin, and glucose levels were evaluated over a 180-min time interval after glucose intake.ResultsA similar proportion of subjects in all three groups shows a GH ratio of & GE; 120% starting from 120 min. Re-considering the definition of paradoxical increase of GH within 90 min, we observed that the prevalence of GH peaks & GE; 120% was higher in acromegaly than in non-acro(& UARR;IGF-1) and non-acro (respectively 42%, 16%, and 7%, both p < 0.001). In patients without GH-Par, a late GH rebound was observed in the second part of the curve. Higher glucose peak (p = 0.038), slower decline after load, 20% higher glucose exposure (p = 0.015), and a higher prevalence of diabetes (p = 0.003) characterized acromegalic patients with GH-Par (with respect to those without).ConclusionsGH-Par response may be defined as a 20% increase in the first 90 min after glucose challenge. GH-Par, common in acromegaly and associated with an increased prevalence of glucose metabolism abnormalities, is found also in a subset of non-acromegalic subjects with high IGF-1 levels, suggesting its possible involvement in the early phase of the disease.

Automated summary

This study aims to evaluate the growth hormone (GH) response in patients with and without acromegaly. It was found that a paradoxical increase in GH levels was observed after glucose intake. The study also revealed a higher prevalence of GH response in acromegalic patients, which was associated with an increased occurrence of glucose metabolism abnormalities.