Letter: Cystic fibrosis: detection of heterozygotes

The alpha 2-adrenergic system of the platelet in cystic fibrosis

The ability of norepinephrine to inhibit prostaglandin E1 (PGE1)-stimulated accumulation of adenosine 3':5' cyclic monophosphate (cyclic AMP) in intact washed platelets was determined in 12 patients with cystic fibrosis, 6 parents of patients with cystic fibrosis, and a total of 21 healthy age-matched controls. Patients with cystic fibrosis and their parents did not differ from their age-matched controls in basal or PGE1-stimulated levels of cyclic AMP, nor in the dose dependent inhibition of cAMP accumulation by norepinephrine. Moreover, binding sites for [3H]-dihydroergocryptine were present in normal numbers and had normal ligand affinity in platelet membranes from patients with cystic fibrosis. In all measures tested, the alpha 2-adrenergic system in the platelet was normal in cystic fibrosis.

Effects of polyamines on platelet aggregation

Polyamines, spermine and spermidine in the micromolar range (1-100 mumol/l) increase ADP and epinephrine-induced platelet aggregation in vitro. The possible rôle of polyamines as regulating factors of platelet aggregation in physiological and pathological states is discussed.