Control In Cellular Activity By Interaction Of Peptides

Abstract

The interaction between compounds of similar structure has been studied, and often provides crucial information on the identity of the receptor subtypes. The information obtained can be applied in therapeutic and preventive medicine. An experiments was conducted in the previous years using EGF, PTH-rP and PTH(1-34) to investigate the interaction between these peptides on the proliferation of JAR human chariocarcinoma cells. Here the interaction between some of the fragments of hypercalcaemic factor PTH-rP and PTH(1-34) were considered with the view to strengthening our earlier argument that PTH-rP and PTH in JAR cells have a receptor which differs from the classical type I receptor present in osteosarcoma SaOS-2 cells and on the other hand to show that fragment of the same or similar compound, could interact with the father peptide and antagonize or agonise its action as this may be one of the methods cells control proliferation, differentiation and other functions. On the other hand it is possible that PTH(1- 34) and PTH-rP(1-34) compete on the PTH/PTH-rP receptor in JAR since effects of PTH(1-34) were only observed at higher concentrations. Potential antagonist action of PTH-rP(7-34) and PTH(1-34) on PTH-rP(1-34) and PTH-rP(186) stimulated cell proliferation were investigated using cell proliferation and DNA assay as an end point. It was found that JAR choriocarcinoma may not have the same receptor as in SaOS-2 and that PTH-rP(7-34) and PTH(1-34) can regulate cell proliferation. Furthermore, fragments of the same peptide may act in an opposing manner providing an insight on how cellular functions are regulated.

Key words: Parathyroid Hormone related peptide (PTH-rP),Parathyroid Hormone (PTH) and Epidermal Growth Factor (EGF).

Nigerian Journal of Physiological Sciences Vol.18(1-2) 2003: 31-34