A recombinant human parathyroid hormone fragment, Pro-Pro-[Arg(11)]hPTH(1-34)-Pro-Pro (MW = 4550 Da), was developed by substituting Arg for Leu at position 11 and adding Pro-Pro at the carboxyl terminus. Following a single injection (0.5-13.5 mu g/bird) of the rhPTH fragment, the serum calcium level in chickens increased 12-42% (P < 0.05) after 1 h as determined by the Parson's Chicken Assay. The functional activity of Pro-Pro-[Arg(11)]hPTH(1-34)-Pro-Pro may be due to removal of the N-terminus Pro-Pro- by X-prolyl dipeptidyl peptidase IV (DPPIV) in vivo, increasing its activity compared to Pro-Pro-hPTH(1-34). This artificial rhPTH fragment could be used to increase calcium mobilization and potentially improve bone health. (C) 2011 Elsevier Inc. All rights reserved.