Effect of octreotide on catecholamine plasma levels in patients with chromaffin cell tumors.
Many chromaffin cell tumors contain somatostatin (SS), and most of them are receptor-positive by in vitro autoradiography and by in vivo administration of radiolabeled SS analogs. We evaluated the effect of a 2-hour infusion of 50 micrograms octreotide on plasma norepinephrine (NE) and epinephrine (E) levels in 6 patients with chromaffin cell tumors. To ascertain the biological activity of octreotide, plasma insulin levels were also measured. Infusion of octreotide was followed in all the patients but 1 by a progressive decrease of plasma NE levels. On the average, plasma NE decreased significantly during octreotide administration, halving its baseline levels at the end of the infusion (51.3 +/- 11.46%, p < 0.05) and rising again slowly thereafter. A slight reduction of plasma E levels was also recorded at the end of octreotide infusion (76.1 +/- 13.77% of baseline, NS) with a prompt return of hormone concentrations to preinfusion values. During octreotide administration, plasma insulin displayed an early and steep fall (49.7 +/- 4.61% of baseline, p < 0.03, at 60 min) with a tendency to escape from inhibition before termination of the infusion. In 5/6 patients, 2 of whom were normotensive before the study and 1 the day of the test, blood pressure did not change during octreotide infusion. In the other patient, blood pressure fell from baseline values of 160/100 to 120/70 mm Hg at 120 min and rebounded to 205/100 mm Hg at 240 min. In conclusion, the short-term administration of low-dose octreotide is capable of lowering NE levels, though with no consistent effect on blood pressure, in patients with chromaffin cell tumors.(ABSTRACT TRUNCATED AT 250 WORDS)
Invitti
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C
2nd Chair of Endocrinology, University of Milan, S. Luca Hospital, Centro Auxologico Italiano, Milan.
De Martin
I
I
Bolla
G B
GB
Pecori Giraldi
F
F
Maestri
E
E
Leonetti
G
G
Cavagnini
F
F
D000310:Adrenal Gland Neoplasms / Q000097:blood / Q000188:drug therapy*; D000328:Adult; D004837:Epinephrine / Q000097:blood*; D005260:Female; D006801:Humans; D007328:Insulin / Q000097:blood; D008297:Male; D008875:Middle Aged; D009638:Norepinephrine / Q000097:blood*; D015282:Octreotide / Q000627:therapeutic use*; D010673:Pheochromocytoma / Q000097:blood / Q000188:drug therapy*
D007328:Insulin; D015282:Octreotide; D009638:Norepinephrine; D004837:Epinephrine