Endocrine Abstracts

Introduction: Somatotropin (GH) and insulin-like growth factor 1 (IGF1) realize their influence on the system of intracellular metabolism and a number of important biochemical lymphocytes reactions through the receptor apparatus. It is allows to use the peripheral blood lymphocytes as the investigations object of intracellular metabolism disorders in acromegaly.

Aim: To study the NAD- and NADP-dependent dehydrogenases activity in blood lymphocytes in patients with active acromegaly.

Methods: The activity of NAD(P)-dependent dehydrogenases in blood lymphocytes was studied in a group of 88 patients (35 men and 53 women) with active acromegaly, mean age 51.0±12.5 years. The NAD(P)-dependent dehydrogenases activity was determined by biochemiluminescence method. The concentrations of GH and IGF1 were measured by ELISA.

Results: In active acromegaly were revealed the decreasing activity of all studied oxidoreductases: glucose-6-phosphate dehydrogenase (P<0.01), NAD-lactate dehydrogenase (LDH) (P<0.001), NADH-LDH (P<0.001), NAD-malate dehydrogenase (MDH) (P<0.001), NADH-MDH (P<0.001), NADP-MDH (P<0.001), NAD-glutamate dehydrogenases (GDH) and NADH-GDH (P<0.001), NADP-GDH and NADPH-GDH (P<0.001), NAD- isocitrate dehydrogenases (IDH) and NADP-IDH (P<0.01 and P<0.001 respectively), glutathione reductase (P<0.001). Our data further observed that decreasing activity of NADP-GDH positively correlated with the basal GH level (r=+0.23, P=0.04) and NADP-MDH activity with IGF1 level (r=+0.30, P=0.008). The low NADH-MDH activity negatively correlated to the basal GH concentration (r=−0.23, P=0.04).

Conclusion: The chronic excess of GH and IGF1 in acromegaly causes a significant depletion of metabolic lymphocytes reserves. The main indicators of functional lymphocytes impairment in acromegaly are: the reduction of intermediates formation for the reactions of macromolecular synthesis and aerobic processes, the low intensity of glycolysis, nitrogen metabolism and inhibition of glutathione complex activity.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.