唾液中テストステロン濃度の加齢に伴う変化についての検討

Abstract

1) Commercial kitを用いた唾液中テストステロンの測定は標準血清を50pg/mlへ希釈し, 標準曲線を作成することで十分可能となり, エーテル抽出操作を含め約5時間で行いえた。2)加齢に伴い唾液中テストステロン濃度が低下し, 40代以降すべての年代で20～30代に比して有意に低下していた。これは血中遊離テストステロンの加齢に伴う変化と同様であった

Measurement of the level of free testosterone is important in the evaluation of testicular function. Because most of the testosterone in the saliva is in the free form, measurement of the salivary testosterone level is considered to be effective for the evaluation of testicular function. In the present study, a commercial kit was employed to measure the salivary testosterone level, and the change in the salivary testosterone level with age was investigated. The subjects of this study were 76 males, 20-89 years of age, with no endocrinological diseases. The concentration of testosterone in the saliva was measured for each of the subjects, and for 34 of the subjects the concentrations of total testosterone and free testosterone in the serum were also measured at the same time. Standard serum was diluted to have a testosterone concentration of 50 pg/ml, and the results indicated that it was sufficiently possible to measure the salivary testosterone. The coefficient of correlation between the salivary testosterone concentration and the serum total testosterone concentration was 0.479 (p < 0.01), while the coefficient of correlation between the salivary testosterone concentration and the serum free testosterone concentration was 0.732 (p < 0.001). These findings thus indicate that the correlation between the salivary testosterone concentration and the serum free testosterone concentration is better than that between the salivary testosterone concentration and the serum total testosterone concentration. It was also demonstrated that the salivary testosterone concentration decreased significantly with aging after the fifth decade of life. The correlation coefficient for that relationship was -0.606 (p < 0.001), and the change was similar to that seen in the serum free testosterone concentration as a function of aging. The findings suggested that measurement of the salivary testosterone concentration with the commercial kit is useful for the evaluation of testicular function.