SEASONAL-VARIATION IN THE ACTIVITY OF 3-MERCAPTOPYRUVATE SULPHURTRANSFERASE OF THE FROG (RANA-TEMPORARIA) LIVER

1. Annual changes in the mitochondrial and cytosolic activity of MPST, GDH as a mitochondrial marker, and total protein content, were studie d in frog (Rana temporaria) liver cells. 2. The variation in the MPST activity in mitochondria, regardless of the sex of the studied animals , is evidently under the influence of the thyroid gland activity, oxyg en consumption and ambient temperature. 3. In the cytosol of the frog liver cells, seasonal changes of MPST specific activity seemed to be r elated to the production of mitochondrial iron-sulphur protein and to the protein-dependent metabolism during the fasting period.