The levels of liver metallothionein and zinc in plaice, <i>Pleuronectes platessa</i> L., during the breeding season, and the effect of oestradiol injection

Abstract

Wild plaice from two locations were examined for liver metallothionein and liver and serum zinc content, before, during and after the breeding season. During the early stages a number of females had very high liver metallothionein and zinc levels. Egg formation and ripening were accompanied by a reduction in serum zinc. In males, the metallothionein levels did not reach such high values and were not correlated with gonad development. There was a correlation between the zinc concentration of the liver and the metallothionein concentration of the liver. Above the threshold value for metallothionein formation, approximately half the additional zinc was found in the metallothionein and half in non‐metallothionein pool(s). Intramuscular injection of oestradiol 3‐benzoate into immature females caused a significant increase in liver weight but a depression in metallothionein concentration relative to the controls.