Microvillar peptidase activity in amniotic fluid: possible use in the prenatal diagnosis of cystic fibrosis.
The activities of two microvillar peptidases, gamma-glutamyl transpeptidase (GGTP) and aminopeptidase M (APM), have been measured in 132 samples of mid-trimester amniotic fluid. These included samples from 16 pregnancies at risk for cystic fibrosis. The activities of both peptidases were significantly below the normal range in amniotic fluids from the 6 affected pregnancies. This points to early pathological changes in fetal tissues in which microvilli are prominent. In contrast, 4-methylumbelliferylguanidinobenzoate-reactive protease activity in amniotic fluid from the 6 affected pregnancies was normal. Correlation of individual values between GGTP and APM was close in all cases examined, so that when a further 7 samples from cases at risk became available they were tested for GGTP alone. Of these, the 3 affected pregnancies had significantly reduced GGTP activity, particularly in the early weeks of gestation. It is suggested that early amniocentesis and examination of gamma-glutamyl-transpeptidase isoenzyme constitution might make possible the reliable early diagnosis of cystic fibrosis.
D000626:Aminopeptidases / Q000378:metabolism*; D000649:Amniocentesis; D000653:Amniotic Fluid / Q000201:enzymology*; D018826:CD13 Antigens; D003550:Cystic Fibrosis / Q000175:diagnosis*; D005260:Female; D005865:Gestational Age; D006801:Humans; D008871:Microvilli / Q000201:enzymology; D011247:Pregnancy; D005723:gamma-Glutamyltransferase / Q000378:metabolism*
D005723:gamma-Glutamyltransferase; D000626:Aminopeptidases; D018826:CD13 Antigens