Screening studies of the psychotropic activity of regulatory peptides under conditions of thyroid hyperfunction

The work is devoted to the screening study of the psychotropic activity of regulatory peptides of a number of glyprolins and melanocortins in conditions of thyroid hyperfunction. Material and methods. The study was carried out on male rats divided into groups: I – intact rats (control); II – individuals with experimental hyperthyroidism; III, IV, V, VI, VII and VIII – animals with induced hyperthyroidism receiving Thr-Lys-Pro-Arg-Pro-Gly-Pro, ACTH(4-7)-Pro-Gly-Pro, ACTH(6-9)-Pro-Gly-Pro, Pro-Gly-Pro, Pro-Gly-Pro-Leu, Arg-Pro-Gly-Pro, Pro-Gly-Pro-Val and Met-Thr-Lys-Pro-Arg-Pro-Gly-Pro, respectively. The behavioural activity of rodents was studied using the «Open Field» test. Results and its discussion. It was found that in the group of rats with induced hyperthyroidism there was an increase in chaotic, disorderly motor activity against the background of a decrease in orienteering and exploratory (crossing the centre, examination of burrows) and an increase in the level of anxiety (defecation, grooming, freezing). The investigated melanocortin and glyproline compounds against the background of thyroid dysfunction had to a greater or lesser extent a corrective effect on the behavioural status of laboratory animals. Conclusions. The results of the screening study of psychotropic activity of glyproline and melanocortin peptides under conditions of thyroid hyperfunction testify to the fact that that the compounds Thr-Lys-Pro-Arg-Pro-Gly-Pro and Met-Thr-Lys-Pro-Arg-Pro-Gly-Pro show the most pronounced effect on behavioural parameters in the «Open Field» test at intraperitoneal administration at doses of 87 and 88 µg/kg/day equal to 1/10 of their molecular weight.