Topical effect of bromocriptine on rat-transplanted human prolactinomas.

In prolactinoma surgery, especially in macro-adenomas, it is not always possible to remove the tumour totally. Cell remnants may cause a regrowth and continue hypersecretion. In order to find out whether tumour remnants could be destroyed by local application of bromocriptine, a research model has been designed. First, prolactin secreting pituitary tumours, removed during surgery, were implanted bilaterally into the brain tissue of rats. In eight rats, the viability of tumour transplants was proven histopathologically and their prolactin secretion was shown immunocytochemically. In a second step, on eight rats, sterile bromocriptine solution was applied topically to the tumour transplants on one side. The other side served as control. Histopathological examination of these treated tissues revealed fibrosis. Immunocytochemical analysis showed no secretory activity. Ultrastructural investigations also revealed evidence of degeneration of the treated cells. The natural course of the transplanted tumour tissues of the other side, as a control group, was also observed during the same 55-day period.