THE ROLE OF LACTIC ACID IN THE REDUCED EXCRETION OF URIC ACID IN TOXEMIA OF PREGNANCY *

Abstract

Wlhen Chesley and Williams demonstrated low uric acid excretion in toxemiiic patients,1 they noted that the reduction in renal urate clearance was rela- tively greater than the reduction in glomerular fil- tration rate (1). This relationship has been con- firmed (2) and is striking when c-ompared with observations on urate excretion in normal slibjects and patients with renal disease. It is gen- erally accepted that tunder normal circtumstances serum urate is completely filtered at the glomertulus and that 5 to 10 per cent of filtered turate ap- pears in the urine (3) ; net tubular reabsorption accounts for the other 90 to 95 per cent. Coombs and co-workers (4), in a sttudy of subjects with various degrees of renal imiipairment, found that as glomerular filtration rate fell, a progressively larger portion of filtered urate was excreted in the urine, uric acid clearance increasing to over 20 per cent of glomerular filtration rate. In pre- eclamptic and eclamptic patients, althotugh glomerular filtration rate is reduced, the ratio of urate clearance to glomerular filtration rate is often lower than normal. Unless there is a redtuction in the filtrability of serum turate, explanation of the low ratio of uric acid clearance to glomiiertular filtra-