In today's VETgirl veterinary CE podcast, we review whether plasma volume expansion occurs in cats after short-term steroid administration. Corticosteroids can have a multitude of effects on the cardiovascular system. Plasma volume is known to increase with corticosteroid administration in cats. Potential mechanisms for plasma volume expansion include mineralocorticoid effects (sodium and water retention via aldosterone receptor activity) and hyperglycemia (with subsequent osmotic fluid shifts) via insulin receptor resistance. Corticosteroids, both endogenous and exogenous, have been demonstrated to have direct effects on myocardial structure and function in humans and dogs, including increased left ventricular wall thickness and diastolic dysfunction. Finally, peripheral vasoconstriction due to corticosteroid activity on vascular smooth muscle may increase afterload.