THE STUDY OF THE RELATIONSHIP BETWEEN THE ACTIVITY OF EPIPHYSIS AND GONADS IN MALE RATS IN DIFFERENT SEASONS

In male rats of different ages, we studied the functional activity of the pineal gland and the gonads during different seasons by determining the levels of melatonin and testosterone in the blood serum. It was found that the highest levels of melatonin observed in male rats in summer and winter, and the lowest - in autumn. The lowest level of melatonin has been established in the group of rats aged 9 months - 127.28+5.11 pmol/l that was 22% lower than the level of melatonin in 3 months old rats (P!0,05), and 20% below the level of melatonin in rats of 15 months old (Ps0,05). The highest level determined in rats aged 3 months (corresponds to the age of man -14 years old), the lowest - in rats 20 months-(corresponds to the age 55-56 years old). At the same time, the low level of melatonin was defined in rats aged 9 months in the autumn (corresponds to the age of man 29-30 years). In the study of testosterone levels in different seasons it was found that the highest level in all age groups presents in autumn, the lowest - in winter. When comparing the levels of testosterone in different age groups, it was determined that the fall of the highest level of testosterone present in the blood of males age 9 months and 15 months, which corresponds to the age of 29-30 and 43-44 of human years. Significant difference between the levels of testosterone in the groups that correspond to the reproductive age - rats of age 3, 9 and 15 months, are present only in the autumn; spring and summer - significant differences between the levels of testosterone absent. The degree of correlation differed in rats of different ages in different seasons: the highest correlation between the levels of melatonin and testosterone was determined in rats aged 9 months in autumn. The correlation coefficients in rats aged 20 months old have been weak - from 0.05 in the spring to 0.17 in autumn that shows the changes in neurohormonal regulation which occur with age.