Similar isoelectric profiles of FSH from gonadotroph cell adenomas and non-adenomatous pituitaries

Heterogeneity of intact FSH in human pituitary tissue was evaluated by the column isoelectric focusing technique, chromatofocusing. FSH was examined from three autopsy pituitaries, one piece of apparently normal pituitary obtained at surgery, three purified FSH preparation, and four gonadotroph cell adenomas. FSH from all of these sources was found to exist in multiple isoelectric forms. FSH from the gonadotroph cell adenomas exhibited chromatofocusing profiles that were similar, both in the range of pI's and the relative proportions of the FSH isohormones, to those of the non-adenomatous pituitaries. We conclude that gonadotroph cell adenomas produce a population of FSH that is qualitatively normal although quantitatively excessive.