Renal function and organic anion and cation transport during dehydration and/or food restriction in chickens

The effect of dehydration in the presence or absence of continued food intake on renal function was evaluated in chickens. In addition, renal transport of organic anions and cations under these conditions was assessed in vitro by uptake of ¹⁴C-para-aminohippuric acid and ¹⁴C-tetraethylammonium bromide by renal slices. Water restriction with continued food intake resulted in increases in serum osmolality and serum concentrations of sodium, uric acid, calcium and total protein. If food was restricted in addition to water, only serum osmolality and sodium concentration were significantly increased after 48 hours. Dehydration with continued access to food resulted in marked decreases in extracellular fluid volume, glomerular filtration rate and effective renal plasma flow. If food was restricted during dehydration, the decrease in effective renal plasma flow was attenuated despite reductions in glomerular filtration rate and extracellular fluid comparable to that seen in dehydrated birds allowed free access to food. Transport of organic anions was significantly increased after 24 and 48 hours of water restriction, regardless of whether food was withheld. Enhanced transport of organic anions in the presence of decreased glomerular filtration rate and effective renal plasma flow during dehydration may promote precipitation of urates and nephrosis in chickens.Abbreviations cpm counts per minute - dpm disintegrations per minute - ECF extracellular fluid - ERPF effective renal plasma flow - GFR glomerular filtration rate - PAH para-aminohippuric acid - SEM standard error of the mean - TEA tetraethylammonium bromide