Comparative in vitro Biological Activity of 1–34 N-Terminal Synthetic Fragments of Human Parathyroid Hormone on Bovine and Porcine Kidney Membranes

Abstract

1–3 4 N-terminal fragments of human parathyroid hormone with sequences according to Brewer et al (hPTH_B) and to Niall et al (hPTH_N) were synthesized and compared for their ability to activate bovine and porcine kidney cortex membrane adenylate cyclase. Results show that these two hormone sequences are able to activate these membranes but at least in this in vitro assay, hPTH_N is about 10 times more active than hPTH_B on bovine as well as on porcine membranes. These “apparent potencies” with respect to the potency of bPTH 1–34 in bovine and porcine membrane assay systems are respectively 4% and 11% for hPTH_B and 39% and 156% for hPTH_N. These relative potencies may be interpreted as corresponding to species specificity of the hormone receptor structural relationships.