Effects of NaHCO₃, α-, and β-adrenergic blockade on albuminuria after swimming in splenectomized dogs

The albuminuria occurring after swimming in splenectomized dogs was investigated. Swimming in splenectomized dogs induces metabolic acidosis, a decrease in renal vascular conductance, and an increase in plasma renin activity, all three factors possibly implicated in the occurrence of albuminuria. The administration of sodium bicarbonate prior to swimming reduced the magnitude of the acidosis and eliminated the increase in albuminuria after swimming. Phenoxybenzamine, an α-adrenergic blocking agent that maintains the renal blood flow during exercise also blocked the increase in albuminuria despite a decrease of blood pH during swimming. However, after metoprolol, a β₁-adrenergic blocking agent that blocks the rise in plasma renin activity during exercise, swimming causes a threefold increase in albuminuria (P<0.01). The albuminuric response to swimming preceded by saline was also significant (P<0.05). It is likely that post-swimming albuminuria in splenectomized dogs is linked to the decrease of renal vascular conductance or to the decrease in blood pH rather than to the rise in plasma renin activity.