PLASMA ENDOTHELIN CONCENTRATION DURING CO LD PROVOCATION IN PRIMARY RAYNAUDS SYNDROME

Plasma endothelin concentration was measured separetely in each hand b efore and after unilateral whole-hand cooling in 23 patients (5 men, 1 8 women; mean age 35.2 [19-52] years) thought to have primary Raynaud' s syndrome (Raynaud's disease). The diagnosis was confirmed, after exc luding other causes, by strain-gauge plethysmography demonstrating col d-induced vasospasm in 8, disproved in 15. In the Raynaud patients (bu t not in the others) the plasma concentration of endothelin on the coo led side increased from 5.13 +/- 0.18 to 6.34 +/- 0.35 pg/ml (P < 0.05 ). On the non-cooled side there occurred a brief rise in endothelin co ncentration from 5.10 +/- 0.18 to 6.23 +/- 0.35 pg/ml (P < 0.05), alth ough there had been no evidence of vasospasm. There had been no differ ence between the two sides in endothelin concentration before the cold provocation. - The results suggest that cold provocation in primary R aynaud's syndrome causes an increase in endothelin Liberation and that this plays a role in the pathogenesis of the vasospasms. Apparently n ot only local but also reflex mechanisms contribute to this.