[Evolution of salivary estradiol levels during the spontaneous menstrual cycle. Correlation between saliva and plasma].

The measurement of steroid concentrations is recommended in the exploration of the different endocrine functions. The salivary concentrations are the reflect of the free biologically active fraction in the plasma. In this study we have used a sensitive and specific method that can be routinely applied in salivary extradiol (SE2) RIA, using a 3 CMO 125I histamine derivative as a tracer. This study related to 12 normal spontaneous menstrual cycles and two abnormal spontaneous cycles. Saliva samples were collected daily throughout the menstrual cycle. Plasma samples were collected simultaneously to compare the salivary and plasma patterns. In the follicular phase SE2 was low: M +/- SD = 9.4 +/- 2.4 pmol/l. During the periovulatory period, the mean level of SE2 the day of the preovulatory peak was 27.6 +/- 8.6 pmol/l. In the luteal phase the SE2 levels fluctuated in a serrated manner with a mean of 11.7 +/- 3.4 pmol/l. The difference between the different phases is significant at the probability threshold 0.01. We have compared the salivary and plasma patterns during the different phases. At the beginning the salivary/plasma ratio was 3.4 +/- 0.9%. During the periovulatory period this ratio was only 2.5 +/- 0.6% and the end of the cycle 2.8 +/- 1%. The statistic study showed that these differences were significant at the probability threshold 0.01.