Baseline and stimulated catecholamine secretion in normotensive patients with active acromegaly: acute effects of continuous octreotide infusion.
OBJECTIVE
Alterations in catecholamine plasma levels may contribute to the cardiovascular complications of acromegaly. Since few data are available on the catecholamine secretory dynamics in active acromegaly and no evidence exists on catecholamine variations during GH decrease, we studied acromegalic patients before and during octreotide administration.


METHODS
We evaluated the catecholamine responses to upright posture and a cold pressure test (CPT) in 11 acromegalic (A) patients before and during continuous administration of octreotide (500 microgram/24h by s.c. pump) compared with 11 normal (N) subjects.


RESULTS
All the acromegalic patients showed left ventricular cardiac hypertrophy. The cardiovascular responses to upright posture were similar between normal subjects and acromegalics both before and during octreotide treatment. The basal levels of norepinephrine (NE) were significantly higher in A patients compared with N subjects (423+/-45 vs 264+/-32pg/ml, P<0. 05) and decreased during therapy (291+/-32pg/ml; P<0.01). The increase in plasma NE during upright posture was significantly lower in A than in N subjects (P<0.01), but was restored to normal during octreotide treatment. CPT increased systolic and diastolic blood pressure, pulse rate and NE plasma levels in N (P<0.05) but not in A subjects both before and during octreotide treatment.


CONCLUSIONS
Our data demonstrate the presence of increased basal NE levels in acromegalic patients with a defective sympathetic response to stimuli. Short-term octreotide infusion is able to induce a reduction in the basal levels of NE and a normalization of the catecholamine response to posture.
Rio
G D
GD
Department of Internal Medicine, Section of Endocrinology and Metabolism, University of Modena, Italy. delrio@unimo.it
Velardo
A
A
Mascadri
C
C
Zalteri
G
G
Papi
G
G
Menozzi
R
R
Giustina
A
A
D000172:Acromegaly / Q000188:drug therapy / Q000378:metabolism* / Q000503:physiopathology*; D000328:Adult; D001794:Blood Pressure; D003080:Cold Temperature; D003971:Diastole; D004837:Epinephrine / Q000378:metabolism*; D005260:Female; D006225:Hand; D006728:Hormones / Q000627:therapeutic use*; D006801:Humans; D007101:Immersion; D007260:Infusion Pumps; D008297:Male; D008875:Middle Aged; D009638:Norepinephrine / Q000378:metabolism*; D015282:Octreotide / Q000627:therapeutic use*; D011187:Posture; D012016:Reference Values; D013599:Systole; D013997:Time Factors
D006728:Hormones; D015282:Octreotide; D009638:Norepinephrine; D004837:Epinephrine