Endocrine Abstracts

Catecholamines can cause hypertension by increasing heart rate and cardiac output or by peripheral vasoconstriction.

Aim of study: The value of plasma and urinary metanephrines and normetanephrines does not correlate with blood pressure in pheochromocytomas.

Material and methods: The lot of study consist of 35 patients with isolated pheochromocytomas diagnosed between 1985 and 2005 in National Institute of Endocrinology C.I.Parhon Bucharest. All patients had high levels of plasma and urinary metanephrines and normetanephrines and the diagnosis has been confirmed by imaging and the pathological examination.

Results: 29 patients (82.9%) had high blood pressure and six patients (17.1%) had normal value of blood pressure. The mean value of plasma metanephrines and normetanephrines was 445.828±127.092 pg/ml respectively 684.966±91.932 pg/ml for patients with high blood pressure and 436.167±107.121 pg/ml respectively 632.000±65.422 pg/ml for patients with normal blood pressure. The mean value of urinary metanephrines and normetanephrines was 1011.690±190.145 μg/24 h respectively 795.000±72.872 μg/24 h for patients with high blood pressure and 930.833±147.391 μg/24 h respectively 768.333±89.536 μg/24 h for patients with normal blood pressure. Althought the mean plasma and urinary metanephrines and normetanephrines values were higher in patients with pheochromocytomas these differences are not statistically significant (P>0.05).

Discussion: There are patients with pheocromocytomas and normal blood pressure althought they have high plasma and urinary metanephrines and normetanephrines. This can be caused by the adrenergic desensitization, can occur in homozygous patients for polymorphism of β2 adrenergic receptors or can be due to various reflex mechanism.

Conclusions: In our lot of study the value of plasma and urinary metanephrines and normetanephrines has not correlated with blood pressure althought their value was higher in patients with hypertension.