Endocrine Abstracts

Context: The nadir serum GH level during glucose suppression (OGTT) is recommended in patients treated by surgery, but not during SA treatment. We have shown that patients considered controlled by SA don’t suppress serum GH during OGTT and have impaired disease-specific QoL as compared to patients controlled by surgery. We hypothesize SA treated patients also don’t suppress GH in response to mixed meals.

Aim: To compare GH levels during two mixed meals in patients considered controlled by either surgery alone or SA.

Patients and methods: Patients controlled by surgery alone (n=22) or SA (n=12) for ≥ 12 months were studied twice in the following order: 1) during a 6 h (8–14 h) GH profile including two standardized mixed meals (at 8 and 12 h), and 2) during a 3 h (8–11 h) GH profile with OGTT at t=9 h. At least 6 months elapsed between each study.

Results: The two groups were comparable at diagnosis as regards gender distribution, serum GH and IGF-I levels and adenoma size. The mean±S.E.M. IGF-I levels (μg/l) at study start were 169±13 (surgery) and 197±13 (SA) (P=0.15). During profile 1 (mixed meal) no suppression was observed in the SA treated group and the mean serum GH levels (μg/l) were elevated [1.55±0.77 (SA) vs 0.68±0.48 (surgery) (P<0.0001)]. During profile 2 (OGTT) fasting GH levels (μg/l) were comparable [1.73±1.30 (SA) vs 1.47±1.57 (surgery) (P=0.60)], but the SA group failed to suppress during the OGTT [2.00±0.90 (SA) vs 0.73±1.0 (P=0.008).

Conclusion: 1) Patients controlled by SA don’t suppress GH in response to either OGTT or mixed meals, 2) This likely implies relatively elevated GH levels during everyday life in SA patients, 3) We recommend that SA patients are assessed with GH measurements during an OGTT and hypothesize that this will reveal under treatment in a substantial proportion of patients.