This study addresses the characterization of human islet-like structures generated from a newly discovered sparse population of precursor cells (Petropavlovskaia and Rosenberg, 2002) in the human pancreas. These cells may be progenitor cells capable of producing pancreatic cells suitable for the treatment of type 1 diabetes. The cells were cultured successfully in non-adherent stationary cultures and yielded, as an important first step, a 1.9-fold expansion in a serum-free medium developed specifically for this cell type. This expanded population grew as pancreatic cell aggregates, which were analyzed for islet-like characteristics. Specifically, through RT-PCR analyses and functionality assays, we show that cells within the population expressed all four of the endocrine hormone genes and proteins (insulin, glucagon, somatostatin, pancreatic polypepticle). As well, the expanded pancreatic precursor cell population exhibited glucose responsiveness although the produced cells appeared to be still primitive in nature. (c) 2005 Wiley Periodicals, Inc.