Effects of certain quinones on renal excretion of sodium

¹ Department of Physiology, Cornell University Medical College, New York City

Coenzyme Q (Q₁₀), an essential of the electron transport system, is located between flavoprotein and the cytochromes. Coenzyme Q consists of a benzoquinone nucleus, having one methyl, an aliphatic and two methoxy constituents. We have attempted to inhibit renal coenzyme Q by the administration of several structural variants directly into one renal artery. Ureteral urines were collected separately for measurement of sodium excretion and renal clearances. Unilateral natriuresis was observed only with aqueous soluble benzoquinones in the oxidized state. The infusion of .001 mmole of one such compound (Q₀) was sufficient to block reabsorption of 17% of the filtered sodium load. Natriuresis did not occur with either reduced quinones or those having a long-chain aliphatic constituent. A moderate increase in the renal clearances of creatinine and PAH was typically, but not invariably, observed. These results suggest that Q₀ blocks the electron transport system and, therefore, some fraction of sodium reabsorption by competitively inhibiting coenzyme Q. This effect may be mediated through energy metabolism.