Linked Life Data

7989464

Source:http://linkedlifedata.com/resource/pubmed/id/7989464

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
1995-1-12
pubmed:abstractText
Although increased plasma norepinephrine (NE) concentrations mediate vasoconstriction during episodic hypertension and hypertensive crises in patients with pheochromocytoma (Pheo), the precise origin of this circulating NE (tumor or sympathetic nerves) is not known. Dihydroxyphenylglycol (DHPG), a deaminated metabolite of NE, is formed principally in sympathetic nerve endings. Under basal conditions, plasma NE and DHPG concentrations correlate closely, and during sympathetic nervous system activation, both plasma NE and DHPG concentrations increase. This observation suggests that plasma DHPG concentrations may reflect the source of circulating NE (tumor or sympathetic nerves) during hypertensive episodes in patients with Pheo. Plasma NE and DHPG concentrations were measured simultaneously, and the NE/DHPG ratio was calculated in seven patients with Pheo during 20 min of sympathetic nervous system activation (treadmill exercise) before and after surgical resection of the tumor. Age- and sex-matched normal subjects were also studied. Exercise resulted in a significant increase in plasma NE and DHPG concentrations in patients with Pheo and in normal subjects (Pheo: basal NE, 1827 +/- 639; peak NE, 3016 +/- 769 pg/mL (P = 0.02); normal subjects: basal NE, 266 +/- 27; peak NE, 1166 +/- 197 pg/mL (P = 0.01); Pheo: basal DHPG, 1521 +/- 280; peak DHPG, 2313 +/- 252 pg/mL (P = 0.007); normal subjects: basal DHPG, 870 +/- 50; peak DHPG, 1630 +/- 180 pg/mL (P = 0.01)]. The NE/DHPG ratio increased with exercise in normal subjects (basal, 0.30 +/- 0.02; peak, 0.83 +/- 12; P = 0.005), but did not change in patients with Pheo (basal, 1.22 +/- 0.32; peak, 1.54 +/- 0.27). Exercise also increased plasma NE and DHPG concentrations and the NE/DHPG ratio in five patients studied after surgical resection of the tumor. Systolic blood pressure and heart rate increased significantly during exercise in all three study groups. The increase in plasma NE and HDPG concentrations during exercise-induced sympathetic nervous system stimulation in patients with Pheo is similar to that in normal subjects and may indicate that the sympathetic nervous system plays an important role in the pathogenesis of hypertension and hypertensive crises in patients with Pheo.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0021-972X
pubmed:author
pubmed:issnType
Print
pubmed:volume
79
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1609-14
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1994
pubmed:articleTitle
Circulating dihydroxyphenylglycol and norepinephrine concentrations during sympathetic nervous system activation in patients with pheochromocytoma.
pubmed:affiliation
Department of Medicine, University of Virginia Health Sciences Center, Charlottesville 22908.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.