Molecular forms of LH subunits in hypergonadotropic states

To determine whether differences in subunits of LH exist in various hypergonadotropic states, we compared the elution profiles of immunoreactive alpha LH and beta LH following gel filtration over Sephadex G-100 (1.6 X 100 cm column) of sera and urinary acetone-insoluble precipitates from normal cycling women during the LH surge and untreated agonadal women and those receiving estrogen replacement. The elution profiles for the alpha subunit were similar in all subjects in both sera and urinary precipitates. In contrast, the elution profiles of beta LH varied between sera and urinary extracts among the 3 groups of subjects. Sera and urinary precipitates from the individual agonadal women eluted identically, but the profiles were distinct from those in samples from each of the cycling women. Exogenous estrogen therapy had no effect on the elution profiles of immunoreactive urinary beta LH in agonadal women but altered the ratios of beta LH/alpha LH excreted to those observed in normal cycling women. These data document the existence of immunoreactive subunits of LH in sera and urinary acetone-insoluble precipitates and confirm the existence of multiple forms of immunoreactive beta LH. The data further suggest that gonadal steroids may modulate the metabolism and/or excretion of beta LH in various hypergonadotropic states.