[Subcellular distribution of the protein kinase activity in the normal and neoplastic thyroid tissue of the rat].

Thyroid tissue has been fractionnated by centrifugation (105 000 q) of its homogenate. Protein-kinase activity in presence of histone is distributed in nuclei (11.5%) mitochondira (22.8%), microsomes (9.8%) and soluble fraction (56%); it is activated by cyclic AMP and GMP, mostly in soluble and nuclear fractions. Protein-kinase activity of total homogenate of neoplasic thyroid (strain 1-5G Wollman) in presence of histone is 3 times higher than in normal tissue and more activated by cAMP. In absence of histone, protein-kinase activity is the more important in mitochondrial and microsomal fractions of normal thyroid and in soluble and nuclear fraction of neoplastic tissue.