Infradian rhythms of alanine aminopeptidase excretion during gentamicin therapy

Urinary excretion of alanine aminopeptidase (EC 3.4.11.2) was examined in 30 patients (22 women, 8 men, range 38-81 years; mean age 55.4) receiving gentamicin in a therapeutic dosage, which was based on the monitored blood creatinine concentration. In general, therapy lasted 10 days. The excretion of 24 individuals displayed significant infradian rhythms with periods between 2.2 and 8.1 days. In 10 of these 24 patients (42%) a circaseptan period was detected. The high portion of circaseptan rhythms might have been induced by the detrimental effects of gentamicin on the proximal tubule and the resulting processes of reconstitution.