[Circadian rhythms in laboratory rats (general characteristics and endocrine aspects)]

The authors present data on the circadian fluctuations of some important functional and biochemical indices in laboratory rats: motor activity, sleep, body temperature, intake of food and water, renal excretion, plasma proteins, glucose, electrolytes, non-organic phosphates and osmolality, hematocrit, corticotropin-releasing hormone (C-RH), adenocorticotropic hormone (ACTH), plasma and adrenal corticosterone, plasma renin activity (PRA), aplasma aldosterone, insulin and antidiuretic hormone (ADH). They describe the participation of the central nervous system in the regulation of circadian rhythms of rats as they present the newest data on the participation of suprachiasmatic hypothalamic nucleus and the sympathicus part of the vegetative nervous system. The significance of knowledge of circadian rhythms for correct interpretation of the obtained experimental data is explained. A mode of work by placing the rats at reverse regimen of lighting is presented. This gives a possibility that the results, obtained from the at night active types of rats, could be compared with those, obtained from the daily active laboratory animals and persons.