A brief history of the study of fish osmoregulation: the central role of the Mt. Desert Island Biological Laboratory.

David H. Evans

doi:10.3389/fphys.2010.00013

Abstract

The Mt. Desert Island Biological Laboratory (MDIBL) has played a central role in the study of fish osmoregulation for the past 80 years. In particular, scientists at the MDIBL have made significant discoveries in the basic pattern of fish osmoregulation, the function of aglomerular kidneys and proximal tubular secretion, the roles of NaCl cotransporters in intestinal uptake and gill and rectal gland secretion, the role of the shark rectal gland in osmoregulation, the mechanisms of salt secretion by the teleost fish gill epithelium, and the evolution of the ionic uptake mechanisms in fish gills. This short review presents the history of these discoveries and their relationships to the study of epithelial transport in general.

Highlights

In 1921, the Harpswell Laboratory, which housed Tufts University’s Summer School of Biology, moved to Mt
The intent of this review is to describe the history of six areas of research that have been important in the study of fish osmoregulation and epithelial transport in general
We found that H+ efflux was dependent upon external Na+ and inhibited by amiloride, suggesting that H+ excretion by the gill epithelium of this marine elasmobranch was via a Na+/H+ exchanger (Evans et al, 1979)

Summary

Introduction

In 1921, the Harpswell Laboratory, which housed Tufts University’s Summer School of Biology, moved to Mt. The basic pattern of marine fish osmoregulation By the late 1920s, it was known that marine teleost fishes were hypotonic to their surrounding seawater and could not produce urine more concentrated than the plasma (reviewed in Evans, 2008). Smith confirmed early studies that the urine was “invariably” isotonic or even hypotonic to the plasma, and that, like the intestinal fluids, the urine contained high concentrations of Mg2+ and SO24+. It is interesting to note that Smith observed that the “osmotic pressure and inorganic composition” of the urine in the goosefish (“possesses a purely tubular kidney”) was similar to that found in the eel and sculpin, both of which have glomerular kidneys. He concluded: “the osmotic pressure and inorganic composition of normal urine is not significantly dependent on the pressure or absence of glomeruli (Smith, 1930).” Since the NaCl concentration was relatively low in both intestinal fluids and urine, www.frontiersin.org

Fish osmoregulation and the MDIBL

Findings

Conclusions