Radioimmunoassay of plasma and salivary progesterone during the menstrual cycle

We have developed specific and sensitive radioimmunoassays for progesterone in saliva (SP4) easily applicable in routine practice to assess ovarian function. One of them uses [³H]progesterone, the other 3-CMO-[¹²⁵I]histamin as tracer. The reliability criteria of both techniques have been controlled and the results obtained with the two methods in 50 saliva samples are correlated well. Our clinical study has been chiefly done with [³H]progesterone. In the present study we reported the values obtained daily during the greatest part of the menstrual cycle in 14 normal cases and they are in agreement with previous reports. The use of [¹²⁵I]tracer, by increasing the sensitivity of the RIA and shortening the duration of the assay, improves the use of SP4 as a practical non-invasive sampling alternative for many clinical situations involving evaluation of the ovarian function.