Search

Urine collected from postmenopausal women, normal men, women and children was prepared by vacuum dialysis and kaolin extraction prior to chromatography on Sephadex G-100. Specific radioimmunoassays for LH, alpha subunit, LHbeta, FSH and FSHbeta were utilized to define the elution patterns of the urinary filtrates, extracts, 2nd IRP-HMG and postmenopausal serum. The following findings were obtained: 1) FSH eluted as a distinct immunoreactive peak whereas LH eluted more diffusely, 2) free alpha subunit was present in all urinary preparations, the 2nd IRP-HMG and postmenopausal serum, 3) free FSHbeta but not LHbeta was detectable in postmenopausal urine, and 4) an LHbeta immunoreactive fragment with an approximate molecular weight of 5000 daltons was present in all urinary preparations and the 2nd IRP-HMG but not in postmenopausal serum.

The usefulness of timed 3-hour urine collections as a substitute for serum gonadotropin (LH and FSH) determinations during the menstrual cycle and during LHRH testing was examined. The timing of the 3-hour urine collection is not important in mature individuals, since no significant temporal trend was found when aliquots were collected every 3 hours throughout two 24-hour periods in one mature woman. Good correlation was found between serum LH and FSH concentrations and the quantity of LH and FSH in timed 3-hour urine specimens throughout normal, ovulatory menstrual cycles in two women. Studies before and during 51 LHRH stimulation tests in normal men, children, and women during different phases of the menstrual cycle and in patients with a variety of hypothalamic-pituitary-gonadal axis disorders were performed. There was good correlation between the quantity of the gonadotropins in time 3-hour urine collections and the mean serum LH and FSH concentrations before and during the LHRH test. The "response area" for serum LH and FSH also correlated well with the amounts of LH and FSH in the urine collected during this period. Therefore, the timed 3-hour urine collection for gonadotropin estimation provides a simple, accurate method for the integration of fluctuating serum concentrations of LH and FSH during such instances of physiologic variability as the menstrual cycle and LHRH stimulation tests.

In response to constant infusion of a submaximal dose of LHRH (0.2 microgram/min for 4 hours), luteinizing hormone (LH) was released in a biphasic pattern in 6 normal men. When the in vitro biologic activity of plasma LH was compared to the immunologic activity throughout the response to LHRH, the B/I ratio remained unchanged (3.6 +/- 0.5, mean +/- SE). Thus, in men the biologic activity of stored LH (acutely releasable) is not different from the presumably newly synthesized hormone that is released as the second pool during prolonged LHRH infusion.