On the activities of parathyroid hormone-like factor and transforming growth factors in extract of pancreatic cancer associated with humoral hypercalcemia of malignancy

Abstract

Extract of exocrine pancreatic cancer associated with humoral hypercalcemia of malignancy was examined for biological activities of PTH-like factor and transforming growth factor (TGF_A and TGF_B), both of which are possible causes of hypercalcemia. The crude extract had both PTH-like and TGF activities. On Bio Gel P-60 column chromatography, PTH-like and TGF_A activities were eluted at around 10 kD, whereas TGF_B activity was eluted at around void fractions, 10 kD and 6 kD. Liver extract, used as a control material, exhibited only TGF_B activity at around 6 kD. CM-cellulose column chromatography of 10 kD fractions resulted in a subtle distinction between PTH-like activity and TGF activities. Further fractionation of the peak with PTH-like activity on reverse-phase high performance liquid chromatography separated PTH-like activity distinctly from TGF_B activity. TGF_A activity was lost through the procedure. It was concluded that the exocrine pancreatic cancer associated with hypercalcemia produced not only PTH-like activity but also TGF_A and TGF_B activities. Several chromatographic analyses suggested that PTH-like activity and at least TGF_B activity stem from distinct molecules and that the PTH-like factor has no significant TGF_B activity intrinsically.