ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

Endocrine Abstracts (2008) 16 P393

A study of the serotoninergic tone in healthy subjects and diabetic patients treated by a clinical-paedagogic approach (Group Care) or traditional care

Marina Trento1, Paola Tibaldi1, Marcella Balbo2, Claudia Kucich1, Margherita Basile1, Enrica Borgo1, Michela Tomelini1, Pietro Passera1, Roberta Giordano2, Emanuela Arvat2, Franco Cavallo3 & Massimo Porta1

1Laboratory of Clinical Paedagogy, Turin, Italy; 2Division of Endocrinology, Turin, Italy; 3Department of Public Health and Microbiology, Turin, Italy.

Background and aims: Alterations of mood and depression may be associated with type 2 diabetes (T2DM) and impaired glucose metabolism in non-diabetic people. Central serotoninergic activity may modulate glucose tolerance via neuroendocrine effectors. The serotoninergic tone was assessed by measuring the hormonal response to a selective serotonin reuptake inhibitor, citalopram, in non-diabetic subjects and patients with T2DM followed by either a traditional approach or a clinico-paedagogic intervention (Group Care) proven to improve quality of life and reduce anxiety.

Materials and methods: Ten healthy subjects (age 53.20±3.92; males=5) and 13 patients with T2DM (age 60.92±3.52, known duration 17.38±5.85, males=10), 7 followed by Group Care and 6 by traditional care, underwent infusions of either citalopram 20 mg or saline over 120 min, in random order, at 8.30–9.00 am after overnight fasting. Samples were taken from an antecubital vein every 15 min for 4 h to measure circulating glucose, insulin, ACTH, free cortisol, DHEA, growth hormone (GH) and prolactin. Hormonal responses were calculated as differences between the areas under the curves after saline and citalopram (Δ-AUC).

Results: Citalopram increased ACTH and cortisol more than saline in healthy subjects (P<0.026 and P<0.011, respectively) and diabetic patients treated by Group Care (P<0.056 and P<0.038) but not in those followed by traditional care. The responses of DHEA, GH, prolactin, insulin and glucose to citalopram did not differ significantly from those to saline in any of the 3 groups. However, in the healthy subjects, basal glucose levels correlated directly with the GH Δ-AUC (r=0.820; P<0.004) and inversely with the insulin Δ-AUC (r=−0.822; P<0.003). The correlation between basal glucose and GH Δ-AUC was preserved in diabetic patients (r=0.637; P<0.026), in whom HbA1c correlated with basal glucose (r=0.657; P< 0.015) and the insulin Δ-AUC (r=0.864; P< 0.012), and the glycaemic Δ-AUC correlated with that of cortisol (r=0.698; P<0.012).

Conclusions: These results suggest that serotoninergic tone may modulate glucose metabolism through opposite effects on ACTH, cortisol, insulin and GH secretion. Diabetes may blunt the response of the pituitary-adrenal axis, though not in patients followed by a long-term intervention model that encompasses clinical as well as cognitive and emotional factors.