Age-related abnormalities of circulating polyamines and diamine oxidase activity in cystic fibrosis heterozygotes and homozygotes.

Serum putrescine (Pu), spermidine (Sd), spermine (Sp), and plasma diamine oxidase ativity (DAO) were determined in cystic fibrosis (CF) homozygotes and heterozygotes plus age-matched controls. Mean (+/- S.E.) levels of Pu (0.51 +/- 0.06 nmoles/ml), Sd (0.63 +/- 0.07 nmoles/ml), and Sp (0.33 +/- 0.08 nmoles/ml) were higher (P < 0.001) in 17 control children versus 16 healthy adults (Pu = 0.15 +/- 0.04; Sd = 0.14 +/- 0.03; Sp = 0 in all). All 4 CF adults tested, but only 3 of 24 CF children, had increased polyamines relative to age-matched controls. Pu (0.33 +/- 0.04), Sd (0.33 +/- 0.05) and Sp (0.16 +/- 0.12) were increased (P < 0.001) in 11 adult heterozygotes; in turn, Pu (0.56 +/- 0.11; P < 0.025) and Sd (0.86 +/- 0.22; P < 0.005) were higher in the adult CF patients than in the heterozygotes. Plasma DAO was higher (P < 0.001) in 45 control children (9.3 +/- 0.7 units/ml) versus 61 healthy adults (5.7 +/- 0.07). Levels greater than or equal to +2 S.D. for controls occurred in 8 (21%) of 39 CF patients. Plasma DAO (19 +/- 4.8) was increased (P < 0.001) in 27 adult heterozygotes; 10 (37%) had values greater than or equal to +2 S.D. for normal adults. One or more polyamines and/or DAO were increased in each of 11 heterozygotes in whom all parameters were measured. These composite abnormalities might be considered as a potential means for identification of asymptomatic CF heterozygotes.