Effect of iodoacetic acid on maintenance of pancreatic endocrine cells of the neonatal rat.

This report describes the specific cytotoxicity of iodoacetic acid (IAA) in selectively destroying the fibroblastoid cells and stimulating the in vitro function of neonatal B cells prepared from rat pancreases. Under culture conditions with a basal medium containing 5.5 mM D-glucose alone, the responses to insulin secretagogues tested were abolished by day 7 of culture. In contrast, the addition of 10 microM IAA enhanced either insulin release evoked by D-glucose (16.7 mM), L-leucine (10 mM) and 2-ketoisocaproate (10 mM) or the cellular insulin content to approximately twice the initial levels (day 0). L-Glutamine (10 mM) augmented the stimulatory effect of L-leucine or 2-ketoisocaproate. Moreover, the continuous application of IAA significantly increased the rates of glutamine oxidation in endocrine cells after 7 days of culture. On the other hand, the IAA-supplemented medium did not preserve the function of A cells. The phase-contrast microphotograph examination revealed the selective removal of fibroblasts from the monolayer cultures. This corresponded very closely with a remarkable reduction in culture DNA content.