GH reserve in subclinical hypercortisolism: evaluation pre- and post-adrenalectomy

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: SAT 26-40-Glucocorticoid Actions & Disease
Saturday, June 15, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board SAT-36
Paolo Beck-Peccoz*1, Serena Palmieri1, Valentina Morelli1, Antonio Salcuni2, Cristina Eller-Vainicher1, Elisa Cairoli1, Volha V. Zhukouskaya1, Alfredo Scillitani2 and Iacopo Chiodini1
1University of Milan, Fondazione IRCCS Cą Granda-Ospedale Maggiore Policlinico, Milan, Italy, 2Casa Sollievo della Sofferenza Hospital, San Giovanni Rotondo (FG), Italy
Introduction. In overt hypercortisolism, GH reserve is decreased and normalized after surgery. In patients with subclinical hypercortisolism (SH), GH secretion has been not fully investigated. In particular, no data about the GH reserve after recovery from SH are available. We assessed GH secretory reserve in AI patients with and without SH and, in the former, before and after surgery.

Methods. We enrolled 24 patients with adrenal incidentalomas, 12 with SH (SH+, 8F/4M, 58.3±6.5 yrs) and 12 without SH (SH-; 11F/1M, 61.8±10.6 yrs). SH was diagnosed in the presence of  ≥2 out of: 1 mg overnight dexamethasone suppression test between 1.8 and 5 µg/dL, urinary free cortisol between 70 and 140 µg/24hrs (n.v. 10-70) and ACTH levels <10 pg/mL. We assessed GH secretion by GHRH+Arginine test (GHRH-ARG) and basal serum IGF-I levels, expressed as SDS (IGF-I SDS, corrected for age). Body mass index (BMI) and insulin resistance index (HOMA-IR) were also evaluated. Eight SH+ patients, who underwent adrenalectomy, were re-evaluated after the restoration of a normal cortisol secretion.

Results.  Age, gender, BMI, HOMA-IR, IGF-I and mean basal GH values were comparable between SH+ and SH- patients. After GHRH+ARG stimulus, the mean GH peak levels (GH-P) and the GH response measured as Area Under Curve (GH-AUC) were significantly lower in SH+ than in SH- Group (15.2±8.1 vs 44.5±30.9 µg/L, P=0.004; 1417.6±802.9 vs 4027.8±2475.7 µg/L/120 min, P=0.002, respectively), even after adjusting for age and BMI. One SH- and 2 SH+ patients had a completely blunted response to GHRH+ARG (GH-P 5.2 µg/L, 5.4 µg/L and 7.7 µg/L, BMI 27.6, 25.6 and 28.2 respectively). In SH+ patients after adrenalectomy GH-P levels and GH-AUC significantly increased as compared to pre-treatment values (23.7±16.3 vs 15.8±10.2 µg/L, P=0.04; 2548.8±1982.2 vs 1617.6±910.8 µg/L/120 min, P=0.072), while IGF-I levels, though increased, did not reach the statistical significance. The two SH+ patients with completely blunted response to GHRH+ARG at baseline, regained a normal response post-adrenalectomy (GH-P 11.6 µg/L and 11.8 µg/L). In the multivariate linear regression analysis, the GH-AUC and the GH-P levels were negatively associated with UFC after adjusting for age and BMI (β= -0.39, P=0.02 and β= -0.4, P=0.02 respectively).

Conclusion. GH secretion appears to be decreased in SH patients and normalizes after recovery. The evaluation of GH secretion could be used as an additional parameter for the diagnosis of SH.

Nothing to Disclose: PB, SP, VM, AS, CE, EC, VVZ, AS, IC

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