The changes which occur in renal excretory function during pregnancy are discussed. The relationship between glomerular filtration rate and effective renal plasma flow is examined in the light of new serial data obtained under conditions of saline diuresis. Changes in the renal handling of nutrients and in the excretion of waste products during pregnancy are reviewed.

Alterations inwater homeostasis can disturb cell size and function. Althoughmost cells can internally regulate cell volume in response to osmolar stress, neurons are particularly at risk given a combination of complex cell function and space restriction within the calvarium. Thus, regulating water balance is fundamental to survival. Through specialized neuronal “osmoreceptors” that sense change...