Aim: To evaluate the impact of rh-GH replacement therapy on neurotransmitters: gamma - amino butyric acid (GABA), dopamine (DA) and serotonin (5-HT) in growth hormone deficient children.                

Research design and methods: This retrospective study included 30 subjects with growth hormone deficit, clinically established: 20 boys (5-14 years) and 10 girls (6-14 years). All of them underwent GH replacement therapy from 9 months - 10.6 years. rh - GH dose varied in all subjects from 0.6-1.9 mg/day based on detailed clinical and anthropometric data. In 2015, all subjects in different phases of treatment were tested for plasma: GABA, DA, 5-HT(Elisa methods) and IGF-1(chemiluminescent method).                

Results: Median plasma GABA in boys vs girls was: 50.5 vs 46 ng/mL; median plasma DA in boys vs girls was: 43.34 vs 29.4 pg/mL; median 5-HT in boys vs girls was: 227.5 vs 208.7 ng/mL and median IGF-1 in boys vs girls was: 334 vs 357.25.7ng/mL. We established a statistically significant difference in plasma GABA and in DA values in boys vs. girls. High multiple regression coefficients were established between age and IGF-1, DA, GABA or between IGF1 and 5-HT, DA, GABA in boys vs. girls.                                    

Conclusion: This study established a link between brain neurotransmitters and the gain in height in GH-deficient children under replacement therapy in different phases of treatment.