28 K cholecalcin (CaBP) levels in abnormal cerebella: studies on mutant mice and harmaline- and 3-acetylpyridine-treated rats.

The cerebellar Purkinje cells of both birds and mammals contain a specific calcium-binding protein, 28 K cholecalcin (CaBP). This is the same protein as the vitamin D-dependent kidney CaBP, but its Purkinje cell level is apparently vitamin D independent. The cerebellar CaBP contents of 3-acetylpyridine- and harmaline-treated rats and 5 mutant mouse strains (Purkinje cell degeneration, reeler, weaver, staggerer and nervous) were measured using a specific radioimmunoassay. The results indicate that the level of cerebellar CaBP is not dependent on the physiological state of the Purkinje cells but is an intrinsic measure of the size of the Purkinje cell population.