Plasma nitric oxide metabolite in women with primary Raynaud's phenomenon and in healthy subjects.
Primary Raynaud's phenomenon (PRP) is characterized by cold- or stress-induced transient attacks of impaired skin circulation in fingers and/or toes. PRP displays seasonal variation with less severe symptoms in the summer. The aetiology has not been clarified. The aims of the present study were (a) to assess the influence of cold exposure on the plasma levels of the nitric oxide (NO) metabolite, nitrate, in patients with PRP and in healthy control subjects; and (b) to investigate whether there is a seasonal variation in these plasma levels. In a group of women with PRP and matched control subjects, venous blood was sampled before and at the end of a 40-min period of whole-body cooling. The study was performed with the same protocol on two occasions; once in the winter and once in the summer. A seasonal variation was detected with higher plasma levels of nitrate in the winter than in the summer, both in PRP and in control subjects. However, the plasma level of nitrate was not changed in response to cold exposure on any occasion, either in the patient or in the control group. Our study indicates that NO formation is up-regulated in response to cold weather in both study groups. However, NO formation does not seem to be increased in response to whole-body cooling, either in PRP patients or in healthy subjects. Further investigations are required to reveal whether the observed seasonal variation in NO formation is a universal phenomenon in man.
Ringqvist
A
A
Department of Clinical Physiology, Göteborg University, Sweden.
Leppert
J
J
Myrdal
U
U
Ahlner
J
J
Ringqvist
I
I
Wennmalm
A
A
D000328:Adult; D003080:Cold Temperature; D005260:Female; D006801:Humans; D016555:Matched-Pair Analysis; D008875:Middle Aged; D009566:Nitrates / Q000097:blood* / Q000652:urine; D009569:Nitric Oxide / Q000378:metabolism*; D011928:Raynaud Disease / Q000097:blood*; D012621:Seasons
D009566:Nitrates; D009569:Nitric Oxide