title: Cytochemical investigation into the Ca-dependence of positive and negative hormonal imprinting in Tetrahymena.
abstract: Insulin gives rise to positive imprinting in Tetrahymena pyriformis, but to negative imprinting in T. thermophila, as revealed by the respective increases and decreases in the insulin-binding capacity of these organisms observed during later interactions with this hormone. We found that changes in insulin-binding capacity exhibited parallelism with fluctuations of the levels of free, intracellular Ca2+ detectable by Quin-2 labeling. An exception was the second interaction of T. thermophila with insulin, which although showing a positive trend, produced a relatively small increase in the level of intracellular Ca2+. These observations suggest an interrelationship between hormone-binding capacity and the fluctuation of intracellular Ca2+ levels. Either hormone binding depends on the availability of Ca2+, or, alternatively, the latter depends on the binding capacity. Further studies are required to elucidate the true nature of this interdependence.
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D006651:Histocytochemistry; D006728:Hormones / Q000378:metabolism*; D007173:Imprinting, Psychological; D007328:Insulin / Q000494:pharmacology; D013768:Tetrahymena / Q000378:metabolism*; D013769:Tetrahymena pyriformis / Q000378:metabolism
chemical_list: D006728:Hormones; D007328:Insulin; D002118:Calcium