IMMUNODETECTION OF PARATHYROID HORMONE-RELATED PROTEIN IN PLASMA AND TISSUES OF AN ELASMOBRANCH (SCYLIORHINUS-CANICULA)

We have used antiserum to human parathyroid hormone-related protein (P THrP) (1-16) to examine tissues and plasma of the dogfish (Scyliorhinu s canicula) for the presence of immunoreactive PTHrP (irPTHrP). The pl asma contained high concentrations of irPTHrP (9.34 +/- 0.37 pM), comp arable to levels in humans with hypercalcaemia of malignancy. Other ti ssues with irPTHrP included brain neurones; epithelial cells of the sa ccus vasculosus, kidney, rectal gland and choroid plexus; and cells of the pituitary pars distalis. PTHrP was not detected in gut, skin, ovi duct, and gill epithelia, nor in branchial cartilage. The principal so urce(s) of plasma PTHrP is not known (C) 1995 Academic Press, Inc.