Developmental Origins of Health and Disease: The developmental environment: effect on fluid and electrolyte homeostasis

Introduction Body fluid and electrolytes in adults are maintained under tight control by complex central and peripheral mechanisms. A relatively minor increase in plasma osmolality, or somewhat larger decrease in plasma volume, triggers counter-regulatory mechanisms in the hypothalamus and kidneys to restore plasma osmolality and/or plasma volume to normal values. Arginine vasopressin (AVP) synthesised in the hypothalamic paraventricular nucleus (PVN) and released into systemic circulation from the posterior pituitary plays a key role in fluid and electrolyte regulation by acting upon renal water channels to conserve water. Other important hypothalamic nuclei, namely the circumventricular organs (CVOs), which are located along the anteroventral wall of the third ventricle, are responsible for regulation of body water and salt content by modulating water and salt intake. CVOs also play a critical role in cardiovascular regulation via efferent connections with brainstem centres regulating sympathetic nervous system responses. The renin–angiotensin system (RAS) is highly expressed within brain centres regulating water and electrolytes and cardiovascular homeostasis. RAS is also highly expressed in the fetal and adult kidney, contributing to normal kidney development in the former. Programming of water and electrolyte regulatory systems is defined as a perinatal ‘insult’ inflicted to the fetus/neonate during critical developmental period(s) which will impact on the water and electrolyte regulatory systems in the offspring. As reviewed, there are significant data demonstrating the perinatal programming of offspring hypothalamopituitary and AVP responses, renal water regulatory mechanisms, thirst and salt appetite, and blood pressure homeostasis in numerous species.