Rapid loss of delta-aminolevulinic acid dehydratase activity in primary cultures of adult rat hepatocytes: a new model of zinc deficiency.

Nonproliferating cultures of adult rat hepatocytes were found to lose 60-70% of cell-associated zinc during their first 24 h of incubation in standard, serum-free medium. The loss of zinc was accompanied by a profound loss (greater than 95%) in the activity of the zinc metalloenzyme, delta-aminolevulinic acid dehydratase, as well as a loss (greater than 85%) in the cellular content of immunoreactive delta-aminolevulinic acid dehydratase protein. Restoration of cellular zinc content by the addition of zinc to the culture medium partially prevented the losses of both delta-aminolevulinic acid dehydratase activity and immunoreactive protein. Since the spontaneous, selective loss of cellular zinc appears to have specific effects on a relevant hepatic function, this culture system constitutes a novel in vitro model of zinc deficiency in mature liver.