The activity of β-glucuronidase in the sweat of subjects with cystic fibrosis, known carriers of the disease, and normal subjects was determined by a spectrofluorometric method by means of 1-naphthol-B-D glucuronide as the substrate. In normal subjects, the enzyme activity was greater in sweat collected during the first five to ten minutes after stimulation, compared to that collected over the next 30 to 40 minutes. There was no substantial difference in enzyme activity of sweat collected during the 30 to 40 minutes after the washout period among normal, cystic fibrosis, and carrier subjects. The Km values of β-glucuronidase activity in sweat from normal and cystic fibrosis subjects were the same.
Evans BW, Kelsch RC, Howatt WF. Beta-Glucuronidase Activity in the Sweat of Children With Cystic Fibrosis. Am J Dis Child. 1974;127(5):660–662. doi:10.1001/archpedi.1974.02110240046004