| Abstract: | The prolactin (PRL) cells of the pituitary are less active in seawater (SW)-adapted eels than in freshwater (FW) ones. The kinetics of their response during adaptation to SW or readaptation to FW was investigated. Morphometric studies show that transfer into SW induces a rapid nuclear atrophy, and a reduction of the cell height and of the amount of cytoplasmic granules. These parameters still continue to decrease slowly for one month, becoming then fairly stable. Readaptation to FW stimulates PRL cells after 2 to 10 days. After one or two months, the cells are similar to those of eels kept in FW. The responses of PRL cells appear to be slower in the eel than in Cyprinodonts, which need PRL to live in FW. A complete adaptation to both environments requires one month at least in Anguilla. |
