Interaction of citrinin and ochratoxin A.

The mycotoxins citrinin and ochratoxin A are produced in common by some molds and have been found together in a number of foods and animal feeds. We used in vitro tests to determine if the same effects are produced by these two mycotoxins when they act both independently and together. Renal cortical cubes prepared from kidneys of young adult Hormel-Hanford miniature swine were cultured in the presence or absence of the toxins for 1 h at 37 degrees C. The concentration of the toxins both singly and in combination ranged from 10(-6) to 10(-3) M. The tissues were incubated, removed, rinsed, and reincubated to measure transport of either tetraethylammonium (TEA) or paraminohippurate (PAH) ions and protein synthesis, using 3H-leucine. The transport data were analyzed by a recently developed logistic function test to ascertain whether the effects were additive, synergistic, or antagonistic. The significance of deviation was tested after a potency multiplier was added to the mixture. Data for three of the five experiments measuring TEA transport indicated a synergistic effect; for the other two, the results were not significantly different from additivity. The same was true for PAH transport. For protein synthesis, one experiment showed synergism; for the other, nonadditivity was not significant. None of the measurements showed antagonism between the two toxins. As with several other systems, tests of biochemical effects showed that administration of citrinin and ochratoxin A together did not elicit either consistent or strong synergistic responses.