A new method simplifying collection of serial specimens for gonadotropin determinations

Patterns of gonadotropin levels have been compared in specimens of serum, 24-h urine collections, and first morning urine voidings collected throughout a menstrual cycle from 8 sexually mature, young women. Quantities of gonadotropins in first morning voidings were found to provide a reliable estimate of 24-h excretion of these hormones and demonstrate the same patterns of change as do serum and 24-h urine specimens. Thus first morning voidings satisfactorily overcome logistical problems inherent is serial serum and 24-h urine sampling for studying gonadotropin excretion patterns.