[Seasonal and circadian fluctuations in blood biochemical indicators in mice in natural conditions and exposed to constant light]. / Sezonnye i sutochnye kolebaniia biokhimicheskikh pokazatelei krovi u myshei v estestvennykh usloviiakh i pri postoiannom osveshchenii.

The fluctuations of activity of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) and those of the levels of protein, glucose, cholesterol, bilirubin, creatinine, blood urea nitrogen, K+, Cl-, Na+ in blood plasma of mice in natural conditions (NC) and exposed to constant light (CL) were studied in different seasons of the year (in January, April, July, October) on days 18, 24, 6 (at 12 o'clock). Most indices both in NC and CL animals had seasonal rhythm similar for each of them. This proves a primary effect of environmental geoclimatic factors of formation of circadian periodicals as compared to desynchronization in constant light revealed by Kosinor analysis in winter (acrophase from 14.16 till 16.32 o'clock) and autumn (acrophase from 23.03 til 4.40 o'clock). During the same seasons one can observe the maximum desynchronization influences of constant light, which leads to abrupt falling (to the 10-fold and more) of the fluctuations amplitude and in some cases to stabilization of circadian rhythm.

[Diurnal rhythm of rectal temperature in mice during various lighting conditions]. / Sutochnyi ritm rektal'noi temperatury u myshei pri razlichnom fotorezhime.

The study of circadian rhythm of rectal temperature (t degrees) during 4.5 months in mice under conditions of continuous lighting (LL) and natural alteration of day and night (LD), considering astronomic time of sunrise and sunset, revealed the following regularities: In winter and in summer t degrees maximum in LD was marked at the beginning of the dark period of time (twilight period), t degrees minimum was observed at the end of the dark period. In winter, when the dark period lasts 14-15 hours, t degrees falls from maximum to minimum during all the dark period (12-14 hours), and in summer, when the period of darkness lasts 6 hours, t degrees falls only during 2 hours. In spring t degrees minimum shifts to the middle of the light period. Under conditions of LL, circadian rhythm of t degrees "splits" periodically into bimodal with periods of 10-14 hours. Long keeping (during 4.5 months) under conditions of LL results in levelling of t degrees circadian rhythm. The character of t degrees circadian rhythm in laboratory animals (mice) is not inverted to that in human beings.