Session: SAT 109-133-GHRH, GH & IGF Biology & Signaling
Bench to Bedside
Poster Board SAT-116
Methods: We studied all patients who underwent GST at Vanderbilt University Medical Center from September 2009 to September 2011. Patients were selected for GST based on history and clinical findings. Comparisons of continuous variables between groups were analyzed using the Mann-Whitney U-test. Spearman correlation was used to determine an association between continuous variables. Results are presented as mean ± standard deviation unless otherwise noted. All data analyses were performed using IBM SPSS Statistics (v. 20).
Results: 26 patients (N=17; 65.4% female) underwent GST and had sufficient laboratory data available for analysis. Mean BMI was 36.4 ± 9.1 kg/m2. Five females (29.4%) were taking an oral estrogen at the time of testing. Six patients (23.1%) had a baseline fasting BG >100 mg/dL on the morning of testing (including 2 with a known diagnosis of diabetes mellitus). The change in BG following GST was not associated with change in GH. While patients with a baseline BG >100 mg/dL had a higher peak BG (187.5 ± 43.3 vs 144.2 ± 24.3; p=0.039) and higher nadir BG (87.0 ± 30.7 vs 60.1 ± 8.5; p=0.013), their peak GH did not significantly differ (p=0.929). Females had a higher peak GH than men (mean 4.4 ± 4.2 vs. 0.8 ± 0.7; p=0.013), and females taking oral estrogen had a higher peak GH than those not taking estrogen (8.2 ± 4.6 vs. 2.8 ± 2.9; p=0.014). There was no linear relationship between peak GH and age or BMI. Mean time of peak GH was 125.8 min ± 68.4 (range 0-210 minutes). Inclusion of GH data beyond 180 minutes did not influence the diagnosis of GHD using a cut-off of 3 ng/dl. There were no serious adverse events. Three patients reported nausea.
Conclusions: Our findings do not demonstrate an association between GH and BG dynamics following GST. Glycemic status at the time of testing did not affect peak GH. Females had a significantly higher GH peak, which may be related to oral estrogen use. The GST was well tolerated, and a testing period of 3 hours is safe and sufficient for the diagnosis of GHD.
Nothing to Disclose: JRW, JKD, VTL, ALU
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