Epithelial cells of the gut, antennal glands, integument, and gills of crus
taceans regulate the movements of ions into and across these structures and
thereby influence the concentrations of ions in the hemolymph. Specific tr
ansport proteins serving cations and anions are found on apical and basolat
eral cell membranes of epithelia in these tissues. In recent years, a consi
derable research effort has been directed at elucidating their physiologica
l and molecular properties and relating these characteristics to the overal
l biology of the organisms. Efforts to describe ion transport in crustacean
s have focused on the membrane transfer properties of Na+/H+ exchange, calc
ium uptake as it relates to the molt cycle, heavy metal sequestration and d
etoxification, and anion movements into and across epithelial cells. In add
ition to defining the properties and mechanisms of cation movements across
specific cell borders, work over the past 5 yr has also centered on definin
g the molecular nature of certain transport proteins such as the Na+/H+ exc
hanger in gill and gut tissues. Monovalent anion transport proteins of the
gills and gut have received attention as they relate to osmotic and ionic b
alance in euryhaline species. Divalent anion secretion events of the gut ha
ve been defined relative to potential roles they may have in hyporegulation
of the blood and in hepatopancreatic detoxification events involving compl
exation with cationic metals.