Endocrine Abstracts

Somatotropin (GH) and IGF1 realise 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 active acromegaly patients.

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: Studying the activity of mitochondrial NAD(P)-dependent dehydrogenases found a decrease in all NAD-dependent oxidoreductase: NADIDH, NADGDH, and MDH (P<0.01), which allows to state the low level flow in the tricarboxylic acid cycle. 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), and glutathione reductase (P<0.001). Our data 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 (P=−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.