This proposal describes experiments that will attempt to elucidate details of the transport functions (i.e. reabsorption from urine to blood) in the avian kidney. Such details for this vertebrate group have been lacking until recently. The bird kidney appears morphologically like a hybrid of kidneys found in reptiles and in mammals. This makes the bird kidney an interesting model for study of the adaptative features of the two kidney types. In addition, the avian kidney appears to possess some transport features that may be unique among vertebrates, and may therefore provide new insight into cellular diversity of function. This work will specifically use micropuncture and electrophysiological techniques to study fluid and electrolyte transport in superficial, "reptilian-type" nephrons. In addition, hormonal regulation of transport activity will be studied.
