PARATHYROID HORMONE-RELATED PROTEIN IS NOT AN AUTOCRINE GROWTH-FACTORFOR NORMAL PROSTATIC EPITHELIAL-CELLS

BACKGROUND. Parathyroid hormone-related protein (PTHrP) is the primary factor responsible for humoral hypercalcemia of malignancy. The hyper calcemic actions of PTHrP occur via stimulation of renal distal tubula r calcium reabsorption and increased osteoclastic bone resorption. The se effects of PTHrP are thought to be mediated through a common parath yroid hormone (PTH)/PTHrP receptor. In addition to the well-establishe d role of PTHrP in bone remodeling, PTHrP is believed to be an importa nt mediator of cellular growth and differentiation in a number of nonb ony tissues. We recently demonstrated abundant expression of PTHrP in normal and malignant human prostatic tissues, and in cultured prostati c epithelial cells. METHODS. In vitro assays were used to test growth- regulatory activity of synthetic and endogenous PTHrP peptides on norm al prostatic epithelial cells. RESULTS. No growth-regulatory activity could be demonstrated. CONCLUSIONS. PTHrP is not an autocrine growth f actor for normal prostatic epithelial cells. (C) 1997 Wiley-Liss, Inc.