Control of Catecholamine Release and Blood Pressure with Octreotide in a Patient with Pheochromocytoma: A Case Report with in vitro Studies

Abstract

A 65-year-old male patient with pheochromocytoma, whose hypertensive episodes were uncontrolled using conventional therapy, was successfully treated with octreotide (SMS 201-995). The serum catecholamine level and the urinary excretion of catecholamines decreased after 300 μg/day of octreotide was administered. To clarify the mechanisms of octreotide that lower catecholamine released from a tumor, we studied the in vitro effects of octreotide on membrane potentials and voltage-dependent Ca²⁺ channel (VDCC) current using the whole-cell patch-clamp technique in single pheochromocytoma cells dispersed after tumor resection. The action potentials were reversibly inhibited with 10 μM octreotide. In addition, the VDCC current evoked by depolarized pulses from the holding potential of –60 mV was inhibited with 10 μM octreotide. Octreotide is useful for controlling blood pressure before surgery in some patients with uncontrolled hypertension caused by a pheochromocytoma.

Effects of somatostatin analog SOM230 on cell proliferation, apoptosis, and catecholamine levels in cultured pheochromocytoma cells

“…In radiolabeled forms (usually 111In-pentetreotide), these analogs are also useful for somatostatin receptor imaging (SRI) (Kaltsas et al 2001, Chrisoulidou et al 2007; however, they bind with high affinity to only sst 2 and sst 5 subtypes (Patel 1999). Although it has been shown that PHEO tissues express more than one sst receptor (Kubota et al 1994, Mundschenk et al 2003, Unger et al 2004, Kolby et al 2006, only a small amount of conflicting data on the role of OCT for PHEO tumor treatment exists (Invitti et al 1993, Plouin et al 1995, Tenenbaum et al 1995, Kopf et al 1997, Koriyama et al 2000, Lamarre-Cliche et al 2002, Zatelli et al 2003, and knowledge of the mechanistic action of SS analogs on PHEO remains incomplete. The poor effectiveness of OCT, for example, might be due to only one (sst 2 ) of the several sst subtypes expressed in PHEO tissues binding with high affinity to standard somatostatin analogs.…”

Effects of slow‐release octreotide on urinary metanephrine excretion and plasma chromogranin A and catecholamine levels in patients with malignant or recurrent phaeochromocytoma

“…Many phaeochromocytomas express a sufficient amount of SRIH receptors to be visualized in vivo using radiolabelled pentetreotide (Tenenbaum et al ., 1995; Kopf et al ., 1997) and we have found that octreotide has antisecretory effects on phaeochromocytoma cells studied ex vivo (Plouin et al ., 1994). Accordingly, two short‐term studies and a few case reports have suggested that octreotide could affect biological and clinical parameters in patients with phaeochromocytoma (De Invitti et al ., 1993; Tenenbaum et al ., 1996; Kopf et al ., 1997; Koriyama et al ., 2000). However, in a double‐blind, crossover, placebo‐controlled study, we found that the short‐term administration of octreotide had no antisecretory effects in patients with benign phaeochromocytoma (Plouin et al ., 1995).…”

“…Three trials tested the acute effects of intravenous or subcutaneous octreotide in a small number of patients with phaeochromocytoma and reported conflicting results (De Invitti et al ., 1993; Plouin et al ., 1995; Kopf et al ., 1997). A few case reports described symptomatic or hormonal improvements following repeated subcutaneous injections of regular octreotide (Tenenbaum et al ., 1996; Koriyama et al ., 2000). The availability of a slow‐release formulation of octreotide − long‐acting repeatable octreotide acetate (Sandostatin LAR®, Novartis Laboratories, Rueil‐malmaison, France) − led us to test the longer term effects of octreotide treatment in patients with malignant or recurrent benign phaeochromocytomas.…”

A Case of Pheochromocytoma with Renal Artery Stenosis and Post-Surgical Watery Diarrhea

“…Recently, Korijima et al [17]reported a case of pheochromocytoma whose hypertensive episodes were controlled by inhibiting catecholamine secretion by octreotide administration. In addition, somatostatin analogues are able to control diarrhea by a direct mechanism on enterocytes of the distal ileum [18].…”