Ryu-Ichi Kitamura

Publications (1)2.03 Total impact

• Article: Conophylline and betacellulin-delta4: an effective combination of differentiation factors for pancreatic beta cells.

  Ryu-Ichi Kitamura, Takeki Ogata, Yuji Tanaka, Kazuo Motoyoshi, Masaharu Seno, Izumi Takei, Kazuo Umezawa, Itaru Kojima
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  ABSTRACT: Conophylline and betacellulin-delta4 reproduce differentiation-inducing activity of activin A and betacellulin, respectively. We examined the effect of conophylline and betacellulin-delta4 on beta cell differentiation. In AR42J cells, conophylline and betacellulin-delta4 converted them into insulin-producing cells. Cells treated with conophylline and betacellulin-delta4 continued to grow after differentiation. Thus, cell number and insulin content were much greater compared to cells treated with activin A and betacellulin. Furthermore, cells treated with conophylline and betacellulin-delta4 secreted insulin in response to glucose. Likewise, conophylline and betacellulin-delta4 converted pancreatic ductal cells into insulin-producing cells. Insulin content, cell number and glucose-evoked insulin secretion were significantly greater than those in cells treated with activin A and betacellulin. Transplantation of pseudoislets prepared using ductal cells treated with conophylline and betacellulin-delta4 was able to reduce effectively the plasma glucose concentration in streptozotocin-treated nude mice. Conophylline and betacellulin-delta4 are effective in inducing differentiation of beta cells from progenitors.
  Endocrine Journal 05/2007; 54(2):255-64. · 2.03 Impact Factor