ABSTRACT
Measurements have been made of the rate of exchange of tritiated water in both intact and hypophysectomized Fundulus kansae in a variety of media.
Hypophysectomy reduces the rate of exchange in fresh water.
Low doses (30 mu) of ovine prolactin stimulate water turnover in hypophysectomized fish in fresh water.
The rate of exchange declines in both intact and hypophysectomized animals with increasing salinity.
Experiments with synthetic solutions show that the decline in the rate of exchange in sea water and in higher salinities is due mainly to the effects of calcium ions.
Fishes maintained in synthetic sea water containing a low concentration of calcium have both a higher rate of exchange of tritiated water and a higher drinking rate than fish in normal sea water.
Supported in part by National Science Foundation Grant GB 7200, and by Biomedical Support Grant Fr-07053 from the General Research Support Branch, Division of Research Resources, Bureau of Health Professional Education and Manpower Training, National Institutes of Health.
Visiting Professor, Zoology Department, University of Missouri, Columbia. Professor Potts’s travel and research was supported by the Faculty Improvement Programme.
Prolactin (NIH-P-S9) was generously supplied by the National Institute of Arthritis and Metabolic Diseases.
