Immunostaining of growth hormone and prolactin in paraffin-embedded and stored or previously stained materials.

In attempts to evaluate immunocytochemically autopsy and biopsy material previously obtained and processed for conventional histologic staining, we had to resort to immunostaining of tissues embedded years ago or even sections already stained with hematoxylin-eosin or aldehyde thionin-PAS-orange G. Hypophysial growth hormone and prolactin proved remarkably resistant to such prior treatment with regard to their antigenic properties, and could be readily immunostained in tissue embedded in paraffin 3-4 years earlier, and after destaining of sections prepared up to 7 years earlier. The results of such "retrospective" immunocytochemical evaluation of autopsy and biopsy materail is illustrated with the staining of "pregnancy cells" for prolactin in the hypophysis of a woman postpartum, the immunostaining for prolactin in the cells of adenomas associated with marked hyperprolactinemia, the staining for growth hormone in adenomas removed from children with gigantism, and the immunostaining for prolactin, growth hormone or both in several adenomas that were discovered at autopsy and not associated with a known clinical history of endocrine aberrations.