Relationship between diurnal rhythm of serum testosterone and two prostatic markers (PSA and PAP) in untreated prostate cancer

Abstract

Objective. To clarify the relation between diurnal rhythm of serum levels of testosterone and two prostatic markers, prostate-specific antigen (PSA) and prostatic acid phosphatase (PAP). Methods. Blood was obtained every four hours during a thirty-two-hour period from fourteen men with untreated prostate cancer. Results. Serum levels of PSA and PAP showed circadian rhythm in 4 and 5 patients, respectively. About half of the remaining patients, the highest or nearly highest peaks of serum levels of PSA or PAP were ob served in the afternoon rather than the morning. In 3 patients, circadian rhythms were not observed in serum levels of PAP, but the fluctuation patterns were the same as those of testosterone and showed synchronous movement. In 7 patients, serum testosterone levels were followed by the same fluctuation pattern for either PSA or PAP after some time delay. Little change in serum levels of PSA was seen throughout the thirty-two-hour period despite large fluctuations of testosterone and PAP levels in 5 patients. Conclusions. Close relation between the fluctuation in serum levels of PSA and PAP, and that in serum levels of testosterone during diurnal periods could be considered. However, the relationship between serum testosterone levels and those of PSA and PAP was ambiguous because of both the difference in the time delay of PSA and PAP in relation to testosterone and the small fluctuation in PSA despite obvious fluctuations in testosterone and PAP in some cases.