Pituitary tumorigenesis and hPit-1 cells.

Despite decades of clinical data verifying the success of therapeutic approaches to human pituitary tumors, a significant number of tumors progress and can be life-threatening. The development of better therapeutic strategies for pituitary tumors is complicated by the relative scarcity of human pituitary material for basic experimentation. Human pituitary tissue was used to derive cell cultures, and a cell line, hPIT-1. Molecular and functional analyses were used to further characterize the cells as human pituitary explants in vitro. Functional analyses of the cell cultures indicated that the cells were tumorigenic and of human folliculostellate origin. hPit-1 cells revealed numerous abnormalities of ploidy. Molecular analyses indicated the absence of expression of the following pituitary hormones or hormone subunits by this culture: growth hormone, prolactin, ACTH, FSHbeta, LHbeta, THbeta, and p-glycoprotein. By contrast, the cells expressed uniformly high levels of human follistatin mRNA. Finally, the cells are moderately tumorigenic in immune-deficient mice. Although the precise molecular genetic mechanisms for tumorigenesis in the established cell culture are unknown, the cells serve as a future resource in the study of pituitary tumor initiation, progression, and response to therapy.