Hypogonadism in a Male with an Immunologically Active, Biologically Inactive Luteinizing Hormone: Characterization of the Abnormal Hormone*

Studies were performed to characterize the LH of a male with hypogonadism attributable to an immunologically active, biologically inactive LH. We wished to determine 1) the biologicalactivity of the LH in in vitro systems and 2) the chromatographic characteristics of LH, FSH, and their subunits in the patient's serum and urine. Before therapy the patient's serum LH was 8.0 ± 0.5 mIU/ml (LER 907), which is significantly higher than in normal men (1.3 ±0.5 mlU±ml; mean ± SD). The response to an LRH infusion was enhanced and biphasic. During the infusion (0.2 µg/min for 4 h) a 3-fold rise occurred at 75 min, and a second rise occurred at 180 min. Basal serumFSH, α-subunit, and LH β-subunit concentrations were also elevated and exhibited an exaggerated rise during the LRH infusion. The in vitro bioactivity of LH in serum and urine, as measured in dispersed rat interstitial cells by means of testosterone (T) and cAMP production, was low in comparison with values found in normal men. There was no significant in...