Ultrastructural study on hepatic melanin in Xenopus laevis.

The livers of Xenopus laevis, grouped by chronological age (0.5, 2 and 3 yrs), were studied electron microscopically. Ultrastructurally most of the melanin granules in the mature female liver showed an internal structure similar to the melanin granules of the oocytes. The hepatic melanin granules of immature females and of all males were pleomorphic and failed to show the characteristic internal structure similar to those of the oocytes. The oocyte is the probable source of most of the hepatic melanin of the mature female.