The ultradian pulsatile release of gonadotropins in normal female subjects

With an original statistical study which employes the analysis of variance and the harmonic analysis, the authors evaluated the levels of LH and FSH obtained from 5 female patients of the infertility clinic. These subjects, apparently free from endocrine disorders, underwent a 7-hour test consisting of samples obtained at 20 minute intervals. By a double-antibody RIA method, we assayed LH and FSH in quintuplicate or triplicate in each sample and counted the tubes twice consecutively. In all subjects for LH and in 3 subjects for FSH we detected a real ultradian pulsatile release of the hormone. Period and amplitude of the LH fluctuations vary according to the phase of the menstrual cycle (follicular phase: short period and low amplitude; luteal phase: long period and high amplitude). No change in amplitude was observed for FSH, while the period in two cases varied in accordance with LH. In two cases we found multiple periods in the fluctuations of one hormone during the same test.