Thymus metallothionein: regulation of zinc-thionein in the aging mouse.

The presence of a zinc-inducible metallothionein in mouse thymus tissue has been shown, together with an age-related modulation of zinc, metallothionein, and thymus mass. Metallothionein (MT) and zinc concentrations were found to be maximum prior to completion of thymic growth and to be at a minimum when development of the thymus had ceased. Subsequent transient outgrowths of the thymus during involution showed similar associated fluctuations of MT and zinc levels. A marked difference in the latter parameters was found on comparison with New Zealand Black mice known for development of early onset autoimmunities. These findings provide a new avenue for both investigation of the regulation of zinc in thymus tissue, as well as the possible elucidation of the molecular basis for certain age-related immune dysfunctions.