Prolactin and interrenal hormone balance in Xenopus laevis adult specimens adapted to brackish water.

We have studied the levels both of serum corticosterone and aldosterone and of prolactin (PRL) specific binding sites (taken by us as an index of circulating PRL) in the cell membranes of the epidermis, kidney, liver and testis in adult specimens of Xenopus laevis gradually adapted to diluted artificial sea water up to 30% concentration, in which they were maintained for two weeks. No significant differences in the values of PRL specific binding to the membranes mentioned above were seen to occur between control animals and those exposed to brackish water. In the specimens kept in brackish water serum aldosterone levels do not differ from those in controls. In contrast, corticosterone values show a statistically highly significant increase. The present findings are discussed with regard to the balance between interrenal hormones and PRL since, in the brackish water-adapted animals, beside the alteration of the corticosterone/aldosterone balance, also that of corticosterone/PRL seems to have occurred.