State of the GABA-ergic system in children with thyroid tumors

GABA concentration in blood of children with thyroid neoplasms exceeds 4 to 7 times that in normal children. After thyroid gland resection for a nodul ar goiter, GABA concentration in the blood of children became normal, after ablation of a malignant tumor a precise relationship was noted between the GABA level in blood and appearance of complications. There was no rise, in nodular goiter, of the GABA level in blood (contrary to what is observed i n normal children after ending a physical load), and in case of cancer the mediator concentration decreased. In children with benign and malignant tum ors of thyroid gland reaction to thyrotropin-releasing hormone and to inhib ition of mediator metabolism by valproic acid was abnormal. After surgery f or a nodular goiter the GABA-ergic system's reaction to physical load was c lose to that in adults, while in patients with thyroid cancer there was no normalization of this reaction whether or not tumor metastases are present. The profile of changes in the GABA concentration in blood after ingestion of valproic acid in patients having been operated for a nodular goiter or t hyroid cancer without metastatic spreading was close to that in normal subj ects, while in the presence of tumor metastases there was no reaction to in hibition of GABA metabolism. No differences have been noted in state of the GABA-ergic system 2 hours after the child falls asleep in different forms of pathology, before or after operation, as well as in the presence or abse nce of metastases.