[Modulation of the circadian rhythm of the glucocorticoid hormone level in mice by thymoptin administration at various times of day].

A study was made of the level of corticosterone in mouse blood plasma after 4-time daily administration of thymopthin (a drug containing 1% of thymosin-alpha 1, synthesized in the All-Union Research Institute of Technology of Blood Substitution and Hormonal Drugs) at a doze of 0.05 mg per mouse in the morning and evening. The object of investigation was blood plasma of CBA male mice aged 12-16 weeks. The investigation was experimental. The purpose was to elucidate a possible role of thymic hormones in the regulation of circadian rhythm of glucocorticoid function of the adrenal cortex. Plasma concentration of corticosterone was determined by concurrent protein binding of hormones. Thymopthin administration was shown to result in change of circadian rhythm of the level of corticosteroids in mouse plasma. Drug administration in the morning elevated daily concentration of corticosterone, that also evening reduced it as compared to the control group that in the received the same volume of physiological salt solution. A curve of the daily time course was obtained as a result of smoothing by a method of the least squares. These results should be taken into account when using thymic drugs for therapeutic and experimental purposes.