Urinary excretion of leucine aminopeptidase in pregnancy.

This paper describes enzyme studies in normal and abnormal pregnancy. Urinary leucine aminopeptidase (L.A.P.) excretion remained relatively low throughout normal single pregnancy. Urinary L.A.P. excretion was, however, raised towards term in four out of five cases of multiple pregnancy, but in one patient the predelivery urinary L.A.P. was not raised, and the second twin in this case died shortly after delivery with gross congenital abnormalities. Urinary L.A.P. was also investigated in ;high-risk' patients. One such patient had excessive loss of this enzyme throughout pregnancy, and in the discussion it is suggested that this could be due to excessive loss of oxytocinase in the urine. Patients with toxaemia were assessed on the basis of foetal survival and the maximum 24-hour pre-delivery urinary levels of leucine aminopeptidase. This urinary value could not be used to predict foetal outcome, but rose to over 120 mg. beta-naphthylamine per 24 hours in the presence of frank proteinuria. If intrauterine death occurred, the urinary L.A.P. value fell gradually. Urinary L.A.P. was also elevated in essential hypertension towards term, but in these patients there was no gross proteinuria.