Clinical evaluation of 99mTc-pyridoxylideneglutamate for hepatobiliary scanning

Clinical evaluation of hepatobiliary scanning using 99mTc-PG was done in twenty normal volunteers and eighty-three patients with liver and biliary tract disease. Satisfactory images of the biliary tract were obtained using small dosages of this agent. In normal humans, the agent reached the liver in 5 minutes, and the common bile duct, gallbladder, and duodenum in 10 to 20 minutes. The gallbladder was not visualized when the cystic duct was obstructed in patients with acute and chronic cholecystitis. In patients with partial common bile duct obstruction, a distended duct was visualized and there was delay in transit of radioactivity into the duodenum. With complete common bile duct obstruction, no radioactivity was seen in the biliary or gastrointestinal tracts up to 24 hours after injection. Hepatocellular disease was characterized by delayed liver clearance and delayed visualization of the biliary and gastrointestinal tracts. There were no toxic or other untoward effects in any patients.     

An overview of Spanish studies on appropriateness of hospital use

A long-acting depot formulation of octreotide (Sandostatin LAR, Sandoz LTD) has been recently developed. Preliminary studies indicated that, in acromegalic patients previously controlled by Sandostatin 300-600 micrograms/day in 2-3 sc injections, the intramuscular administration of 20-30 mg of Sandostatin LAR achieved, during one month a similar control of GH hypersecretion. In the present study, the variations of plasma levels of octreotide, GH and IGF1 were followed during 2 months in acromegalic patients receiving a unique injection of 20 mg (n = 4) or 30 mg (n = 4) of Sandostatin LAR. Following Sandostatin LAR 20 mg i.m, the baseline values of GH (8.1 +/- 2.5 micrograms/l) and IGF1 (684 +/- 92 micrograms/l) were normalized after 2 weeks and remained into the normal range during the 28 following days. Similar results were obtained, after a 30 mg i.m administration of Sandostatin LAR. In this later case, the maximal inhibition of GH and IGF1 (1.3 +/- 1.0 micrograms/l and 392 +/- 266 micrograms/l respectively) lasted 2 months. These data showed that a monthly injection of Sandostatin LAR (20-30 mg) allowed a correct control of GH hypersecretion in this series of acromegalic patients.     

Antifibrotic and hemodynamic effects of the early and chronic administration of octreotide in two models of liver fibrosis in rats

The aim of this study was to assess the effect of the early and chronic administration of octreotide in the prevention of hepatic fibrosis and portal hypertension (PHT). Two experimental models of liver fibrosis caused by bile duct ligation (BDL) or CCl4 were divided into 4 rat groups: sham, placebo, and octreotide (10 and 100 micrograms/kg twice daily, subcutaneously). Liver fibrosis was assessed by the area of fibrosis (image analysis), liver hydroxyproline and fibronectin mRNA contents, and serum hyaluronate. Systemic and splanchnic hemodynamic changes were also evaluated, including the splenorenal shunt blood flow by the transit-time ultrasound (TTU) technique. In both models, splenorenal shunt blood flow was significantly lower in the octreotide groups than in the placebo group (P <.05), while portal pressure was not significantly decreased. There was a significant decrease in fibrosis by octreotide in the CCl4 model only: area of fibrosis: 13.9% +/- 3.7% vs. 9.8% +/- 2.5% (P <.01), hydroxyproline: 1.8 +/- 0.6 vs. 1.3 +/- 0.4 mg/g wet liver (P <.05), respectively, placebo vs. octreotide 10 micrograms/kg. There was a significant correlation between the area of fibrosis and hydroxyproline liver content (r =.87 in the biliary model and r =.91 in the CCl4 model; P <.0001). The early and chronic administration of octreotide prevents the development of portocollateral blood flow without reducing portal pressure in two models of liver fibrosis and the development of liver fibrosis in the CCl4 model.     

Effects of octreotide on biliary lipid composition and occurrence of cholesterol crystals in patients with acromegaly. A prospective study

Treatment with the somatostatin analog octreotide is associated with increased gallstone formation. The mechanism of formation of these stones is unclear. The purpose of this study was to examine the effect of a three-month treatment with octreotide on biliary lipid composition and the occurrence of cholesterol crystals in patients with acromegaly. Thirteen patients with active acromegaly, aged 24-76 years, received octreotide (100 micrograms three times daily) for three months. Fasting gallbladder bile was obtained during upper gastrointestinal endoscopy after ceruletide stimulation. Bile was studied before and at the end of the treatment period (N = 7), only before (N = 4), or only at the end of treatment (N = 2). Before treatment, all bile samples but one were supersaturated with cholesterol. However, none contained cholesterol crystals on microscopic examination. At the end of the treatment period, all but two samples were supersaturated with cholesterol. Three of nine samples contained cholesterol crystals, a proportion significantly higher than before treatment. The relative proportions of bile acids, cholesterol, and phospholipids, and the mean cholesterol saturation index were not different before and during treatment. Follow-up ultrasonography showed the occurrence of gallstones in four patients, including the three patients who had cholesterol crystals. We conclude that: (1) fasting gallbladder bile of patients with acromegaly is frequently supersaturated with cholesterol; (2) treatment with octreotide does not increase cholesterol saturation index, but may induce the occurrence of cholesterol crystals. The data are consistent with the view that gallstones induced by octreotide are cholesterol stones and suggest that the drug may impair gallbladder motility and/or decrease cholesterol nucleation time.     

Assessment of biliary excretion of piperacillin-tazobactam in humans

Piperacillin-tazobactam concentrations in serum and bile were measured intraoperatively in 10 patients undergoing cholecystectomy (group 1) and 5 cholecystectomized patients provided with external bile duct drainage (group 2). Each patient received a single intravenous dose of piperacillin at 4 g plus tazobactam at 0.5 g over 30 min. Drug concentrations in both serum and bile were measured by high-performance liquid chromatography. In group 1 patients, serum and bile specimens and gallbladder wall fragments were collected at mean times of 70 and 83 min postinfusion, respectively. The mean concentrations of piperacillin and tazobactam were, respectively, 69.1 +/- 41.5 (standard deviation) and 9.9 +/- 5.1 microg/ml in serum, 630.4 microg/ml (range, 24.8 to 1,194 microg/ml) and 11.8 microg/ml (range, 3.6 to 22 microg/ml) in choledochal bile, 342.3 microg/ml (range, 1.1 to 1,149 microg/ml) and 7.7 microg/ml, (range, 0.2 to 23.1 microg/ml) in gallbladder bile, and 49.3 microg/g (range, 9.7 to 223 microg/g) and 2.9 microg/g (range, 0.1 to 5.9 microg/g) in the gallbladder wall. In group 2 patients, the amounts of drugs recovered in bile drainage obtained over 12 h were 28.4 +/- 18.0 and 1.0 +/- 0.5 mg for piperacillin and tazobactam, respectively. Peak piperacillin and tazobactam concentrations in bile reached 358 +/- 242 and 10.8 +/- 4.2 microg/ml, respectively. Comparison of drug levels in serum and bile suggests an underlying active secretion process for piperacillin elimination into the bile, unlike that of tazobactam. From a therapeutic viewpoint, given the concentrations of tazobactam recorded in bile fluid and tissue, the addition of this beta-lactamase inhibitor to piperacillin therapy might be of interest in the management of biliary tract infections, mostly in patients at risk of mixed aerobic-anaerobic infections due to beta-lactamase-producing organisms.     

Randomised trial of octreotide for long term management of cirrhosis after variceal haemorrhage

OBJECTIVE: To assess the efficacy of long term octreotide as adjuvant treatment to programmed endoscopic sclerotherapy after acute variceal haemorrhage in cirrhotic portal hypertension. DESIGN: Randomised clinical trial. SETTING: University hospital. SUBJECTS: 32 patients with cirrhotic portal hypertension. INTERVENTIONS: Programmed injection sclerotherapy with subcutaneous octreotide 50 micrograms twice daily for 6 months, or programmed injection sclerotherapy alone. MAIN OUTCOME MEASURES: Episodes of recurrent variceal bleeding and survival. RESULTS: Significantly fewer patients receiving combined octreotide and sclerotherapy had episodes of recurrent variceal bleeding compared with patients given sclerotherapy alone (1/16 v 7/16; P = 0.037, Fisher's exact test), and their survival was significantly improved (P < 0.02, log rank test); this improvement was maintained for 12 months after the end of the study. Combined treatment also resulted in a sustained decrease in portal pressure (median decrease -6.0 mm Hg, interquartile range -10 to -4.75 mm Hg, P = 0.0002) compared with sclerotherapy alone (median increase 1.5 mm Hg, interquartile range 0.25 to 3.25 mm Hg), as well as a significant improvement in liver function as assessed by plasma concentrations of bilirubin, albumin, and alanine aminotransferase and by hepatocyte metabolism of aminopyrine labelled with carbon-14. CONCLUSION: Long term octreotide may be a valuable adjuvant to endoscopic sclerotherapy for acute variceal haemorrhage in cirrhotic portal hypertension.     

Prevalence of symptoms related to asthma in Guadalajara

PURPOSE: We studied the effects of octreotide and ursodiol on the gallbladders of patients with acromegaly. METHODS: We performed gallbladder sonography in patients with acromegaly at various intervals during treatment. Group I (18 patients) was treated with subcutaneous injections of the somatostatin analogue octreotide. Group II (10 patients) was treated with ursodiol while receiving octreotide therapy. RESULTS: Seventy-eight percent of patients receiving octreotide developed gallbladder abnormalities: sludge in 72% (13/18) and calculi in 39% (7/18). Ursodiol reversed the gallbladder abnormalities in 7 of 10 patients. CONCLUSIONS: A majority of patients receiving octreotide develop gallbladder abnormalities. Ursodiol appears to reverse the abnormalities in most cases.     

Predictive value of antepartum ultrasound examination for anomalies in twin gestations

RATIONALE AND OBJECTIVES: We investigated the potential of manganese (III) mesoporphyrin (Mn-mesoporphyrin) as a hepatobiliary contrast agent for magnetic resonance (MR) imaging in rabbits given VX-2 carcinoma liver implants. METHODS: Rabbits given VX-2 carcinoma liver implants (n = 8) were imaged before and after the intravenous (i.v.) administration of 0.04 mmol/kg Mn-mesoporphyrin. MR images were correlated with gross-specimen cross-sections. The distribution of Mn in various tissues following i.v. administration of 0.04 mmol/kg Mn-mesoporphyrin was determined using atomic absorption analysis. A standard panel of serum chemistries was followed over 7 days in six rabbits following this same dose of Mn-mesoporphyrin and compared with chemistries from two control rabbits. RESULTS: I.v. administration of 0.04 mmol/kg (25 mg/kg) Mn-mesoporphyrin resulted in improvement of tumor-to-liver contrast, with enhancement of normal liver (99.7 +/- 14.7%) and the gallbladder (442 +/- 116%), but not VX-2 tumor tissue (14.8 +/- 13.9%), (n = 8, p = .05). Analysis of tissue Mn levels 100 min after i.v. Mn-mesoporphyrin injection demonstrated preferential distribution of Mn to normal liver tissue (57.8 +/- 15.3 micrograms Mn/g) compared with VX-2 tumor (4.28 +/- 1.48 micrograms Mn/g). No significant change was found in the serum chemistries of six normal rabbits over a 7-day period after the i.v. administration of 0.04 mmol/kg Mn-mesoporphyrin. CONCLUSION: I.v. Mn-mesoporphyrin improved lesion-to-liver contrast because of preferential distribution of Mn-mesoporphyrin to normal liver parenchyma and bile.     

In vivo responsiveness of morphological variants of growth hormone-producing pituitary adenomas to octreotide

The somatostatin analog, octreotide, is an inhibitor of growth hormone (GH) secretion that has been used to treat patients with GH-producing pituitary tumors. In this study we investigated the in vivo responsiveness to treatment with this analog in patients harboring different morphological types of GH-producing pituitary adenomas. Both GH and insulin-like growth factor I (IGF-I) plasma levels in 30 patients treated with octreotide (300 micrograms/day) for 4 months preoperatively were compared with those from 30 patients who did not receive treatment preoperatively. Tissue samples were studied using ultrastructural and immunohistochemical techniques. Amongst patients harboring densely granulated (DG) adenomas, mean GH levels were reduced to 32 +/- 9% by octreotide, to 30 +/- 7% by surgery and to 26 +/- 9% of baseline by both interventions. Surgery was equally as effective in lowering GH levels in patients with sparsely granulated (SG) adenomas as it was in those with DG adenomas; in patients with SG adenomas, GH levels were reduced by surgery alone to 37 +/- 16% and to 24 +/- 15% when performed following octreotide pretreatment. In contrast, treatment with octreotide alone in patients harbouring SG adenomas reduced GH levels to only 70 +/- 13% of baseline (p < 0.02 compared to surgery alone, or surgery and octreotide). We conclude that the GH inhibitory effects of octreotide are significantly better in patients harboring DG somatotroph adenomas compared with those harboring SG adenomas.     

Gallbladder motility and cholecystokinin release during long-term enteral nutrition in patients with Crohn's disease

BACKGROUND: Gallbladder bile stasis during long-term continuous enteral feeding may contribute to the high prevalence of gallstones in patients with Crohn's disease. We therefore examined the effects of continuous enteral nutrition on gallbladder motility and cholecystokinin (CCK) release in six patients. METHODS: Gallbladder volume was measured ultrasonographically for 12 h on days 1 (start), 8, 22 (6-h interruption of enteral feeding), 36, and 43 (end) of enteral feeding. Plasma CCK was assessed at several time points. RESULTS: Initial fasting gallbladder volume was 19.3 +/- 4.5 (mean +/- SEM) ml, which decreased to 4.9 +/- 3.6 ml after start of feeding. CCK increased from 1.5 +/- 0.3 to 3.9 +/- 1.1 pmol/l. On days 8 and 36 the gallbladder was almost completely contracted, and CCK increased to 7.5 +/- 2.7 and 8.3 +/- 2.6 pmol/l, respectively. On days 22 and 43 gallbladder volume increased, and CCK decreased rapidly to fasting concentrations after interruption of feeding. CONCLUSIONS: During continuous enteral nutrition the gallbladder is completely contracted, and CCK concentrations remain elevated. It is therefore unlikely that long-term enteral nutrition contributes to the increased prevalence of gallstones in patients with Crohn's disease.     

Indium-111 pentetreotide single-photon emission tomography in patients with TSH-secreting pituitary adenomas: correlation with the effect of a single administration of octreotide on serum TSH levels

Few data are available on the visualization of somatostatin receptors in vivo in patients with thyrotropin (TSH)-secreting adenoma. We studied five patients with TSH-secreting adenomas using single-photon emission tomography (SPET) after administration of indium-111 pentetreotide. The intensity of 111In-pentetreotide uptake by the tumours was correlated with the degree of TSH suppression after a single administration of 100 microg octreotide s. c. Five patients (three women and two men) aged 27-46 years were investigated. Except for one patient with acromegaly, all had pure TSH-secreting tumours. One patient was previously untreated, while two had received octreotide, one antithyroid drugs, and one radioiodine. In all patients SPET demonstrated increased uptake of 111In-pentetreotide by the pituitary adenoma. The target to non-target ratio (T/nT) of 111In-pentetreotide uptake was higher than 10 in three patients. Administration of 100 microg octreotide s. c. caused a significant reduction in TSH levels from 4.8+/-1.4 mU/l to a nadir of 3.1+/-1.1 mU/l after 6 h (P<0.001 by ANOVA). Suppression of TSH secretion ranged from 30% to 60% of the baseline value. The T/nT ratio showed a trend toward a direct relationship with the degree of TSH inhibition after acute octreotide administration (r=0.67; P=NS). Our study showed that 111In-pentetreotide scan visualized somatostatin receptors in all five of the patients with TSH-secreting pituitary adenomas, confirming the frequent presence of somatostatin receptors in these rare tumours, even though the correlation with the TSH inhibition after a single administration of octreotide did not reach significance.     

Applying radiobiological principles to combined modality treatment of head and neck cancer--the time factor

Although gallbladder stasis exists in most patients with cholesterol gallstones, it is unknown whether stasis is a causative factor of gallstone disease or merely a consequence of it. We studied the impact of sustained gallbladder stasis induced by a cholecystokinin (CCK)-A receptor antagonist (MK-329) on gallstone formation in ground squirrels fed either a trace or a high-cholesterol diet. MK-329 markedly inhibited gallbladder contraction in vitro in response to CCK (at EC100, control: 3.6 +/- 0.5 vs. MK-329: 1.1 +/- 0.3 g; P < .05) and increased gallbladder fasting volume in vivo (control: 462 +/- 66 vs. MK-329: 1,004 +/- 121 microL; P < .05). Whereas the high-cholesterol diet alone (1%-cholesterol diet + placebo) increased the cholesterol saturation index (CSI) in control animals (trace-cholesterol diet + placebo), MK-329 significantly (P < .05) decreased the CSI in both hepatic and gallbladder bile in animals on the trace-(trace-cholesterol diet + MK-329) as well as on the high-cholesterol diets (1%-cholesterol diet + MK-329). The mucin content of the mucus layer on the epithelial surface of the gallbladder wall more than doubled (P < .05) with the high-cholesterol diet; adding MK-329 to the latter group produced a further 82% increase (P < .05). The cholesterol diet + MK-329 group had the highest (100%) incidence of cholesterol crystals that were evident in fresh gallbladder bile, coincident with a shortened nucleation time (2.5 +/- 0.6 days; P < .05 vs. the cholesterol diet + placebo group, 5.8 +/- 1.0 days or the other 2 groups, >21 days). Bile from animals on the trace-cholesterol diet, whether or not receiving MK-329, lacked crystals in bile and exhibited a normal nucleation time (>21 days). Thus, stasis per se may lower the CSI, but its detrimental effect on the gallbladder predominates locally, and so accelerates cholesterol crystal formation in this model.     

Effect of endoscopic sphincterotomy on gallbladder motility

In experimental animals, sphincterotomy facilitates passage of solids from the gallbladder and inhibits gallstone formation apparently by improvement in gallbladder emptying. In humans, however, gallbladder emptying has not been studied following endoscopic sphincterotomy (ES) in patients with gallstones. We therefore prospectively studied resting and cerulin-stimulated gallbladder volumes by real time ultrasonography in 15 patients of choledocholithiasis with gallbladder in situ (eight with and seven without gallbladder calculi) before and after (after bile duct clearance) ES. ES significantly lowered resting gallbladder volume (21.2 +/- 10.6 vs 11.1 +/- 5.0; P < 0.0001) and cerulin-stimulated residual gallbladder volume (10.8 +/- 5.6 vs 4.4 +/- 2.1; P < 0.0001). ES also significantly increased the gallbladder ejection fraction (47.3 +/- 12.1% vs 58.8 +/- 11.1%; P < 0.0001). The rate constant for gallbladder emptying after cerulin infusion also increased significantly after ES (-0.022/min vs -0.031/ min; P < 0.0001). Significant improvement in gallbladder motility was observed in both groups of patients with and without gallbladder calculi. ES significantly improves gallbladder motility in humans.     

Long-term treatment with cabergoline, a new long-lasting ergoline derivate, in idiopathic or tumorous hyperprolactinaemia and outcome of drug-induced pregnancy

Cabergoline (CAB), a new long-acting ergoline derivative, was shown to be very effective in reducing PRL levels in normal volunteers and in hyperprolactinemic patients. We evaluated the hormonal changes after discontinuation of long-term therapy with CAB as well as the safety of drug exposure during pregnancy both for mothers and babies. We therefore studied 48 patients (47 females and one male) with pathological hyperprolactinaemia (mean +/- SE, 117.2 +/- 15.2: median 73.2 micrograms/l), treated for 1-82 months (mean +/- SE, 28.3 +/- 3; median 18). After long-term treatment, CAB was withdrawn in 11 patients and PRL levels were persistently normal for almost 15 days and significantly lower (p < 0.05) than basal at 30, 45, 60, 90, 120 days. Three patients had normal PRL levels still at 45 days after treatment discontinuation. Nine patients became pregnant after 1-37 months (mean 12.4) of therapy. In two patients the pregnancy was interrupted spontaneously in one case and voluntarily in the other. In all but one patients after delivery or three-month breast feeding, PRL levels trended towards reduction. In two cases (one with microadenoma and one with idiopathic hyperprolactinaemia) PRL remained in the normal levels for 1-3 years after delivery. In conclusion CAB is able to inhibit plasma PRL levels for long time (up to 120 days) after withdrawal in patients with pathological hyperprolactinaemia treated with long-term therapy.     

Use of intraoperative laparoscopic sonography in the diagnosis of hepato-pancreatic-duodenal duct diseases

Laparoscopic doppler sonography was conducted in 245 patients. Its application have permitted to diagnose the diseases of gallbladder, pancreas, liver, common bile duct, duodenum, to determine the inflammation form, to substantiate the extent and tactics of surgical intervention and to reduce the complications frequency.     

32P-postlabelling studies of target tissues and bile from patients with familial adenomatous polyposis and from unaffected controls

Patients with the inherited form of colon cancer, familial adenomatous polyposis (FAP), are at high risk of developing duodenal adenomas and carcinomas. The periampullary clustering of these neoplasms suggests that bile plays a role in their development. We investigated this theory using 32P-postlabelling to detect DNA adducts. We found significantly higher adduct levels in duodenum of FAP patients than in unaffected controls, and higher levels in duodenum than stomach. Levels of adducts were significantly higher in the small bowel of rats gavaged with FAP gallbladder bile than in the small bowel of those that received control gallbladder bile. We found that bile from FAP gallbladder produced significantly more DNA adducts than control gallbladder bile when incubated with salmon sperm DNA in vitro. These results support the hypothesis that the bile of FAP patients may be involved in the development of duodenal adenomas in these patients.     

Octreotide for treatment of postoperative alimentary tract fistulas

Eighteen patients with postoperative fistulas of the gastrointestinal tract were treated with the somatostatin analog octreotide between November 1989 and November 1992. Fourteen patients had enterocutaneous fistulas: seven from the duodenum and seven from the ileum. Another three patients had pancreatic fistulas, and one patient had a biliary fistula. Within 24 hours of octreotide treatment, a mean reduction of 52% in the intestinal fistulas' output, 40% in the pancreatic fistulas, and 30% in the biliary fistula was noted. In the intestinal fistulas group the closure rate was 72% after a mean of 11 days. Early closure (mean 6 days) was achieved in all three pancreatic fistulas. In the patient with the biliary fistula a 30% reduction was observed twice following the administration of octreotide, and an increase occurred when it was withheld. The reduction rate of the secretions in high-output intestinal fistulas (> 500 ml/day) was higher than in the low-output fistulas (63 +/- 8% versus 39 +/- 4%, p < 0.05). Fistula output and the initial response to octreotide treatment had no value in predicting spontaneous healing. In conclusion, octreotide is a valuable tool for the conservative treatment of fistulas of the digestive tract. It is especially valuable for management of high-output enteric fistulas and pancreatic fistulas.     

The potential site of disordered gallbladder contractility during the early stage of cholesterol gallstone formation

BACKGROUND/AIMS: Feeding a high cholesterol diet to dogs causes a reduction in gallbladder smooth muscle contractility with a consequent stasis. Gallbladder stasis is an important link between the hepatic secretion of cholesterol saturated bile and the formation of cholesterol gallstones. METHODOLOGY: In this study we tried to localize the probable site of gallbladder smooth muscle dysfunction in a well established animal model of cholesterol gallstone disease. Adult male dogs were fed either a high or low cholesterol diet (control group). Strips of gallbladder smooth muscle for tension development were stimulated with two groups of agonists and dose response curves were plotted for all agonists used. RESULTS: The forces developed in response to the first group of agonists, the cell membrane-active agonists, e.g. acetylcholine, cholecystokinin, and potassium chloride were decreased in high cholesterol fed dogs with an increased cholesterol saturation of bile when compared to the control group. On the other hand, the contractile response showed non-significant differences between the test and the control group on using the second group of agonists that bypass the intact sarcolemmal membrane and stimulate directly either the contractile mechanism, e.g. barium, or the intracellular signal transduction pathways e.g. aluminum fluoride. CONCLUSION: We conclude that the smooth muscle defect responsible for disordered gallbladder contractility in high cholesterol fed dogs most probably involves the sarcolemmal membrane.     

Effect of octreotide on human sphincter of Oddi motility following liver transplantation

The effect of octreotide on sphincter of Oddi motility was investigated in six liver transplant patients, employing percutaneous (through the T-tube tract) manometry. Continuous and simultaneous sphincter of Oddi and duodenal motor activities were recorded before and for 60 min after the administration of octreotide (100 micrograms subcutaneously) and after the injection of cholecystokinin (0.02 microgram/kg intravenously). With octreotide, contraction frequency and basal pressure significantly increased (P < 0.05). This effect lasted more than 60 min, long after octreotide-induced duodenal migrating motor complex phase III activity had ceased. Sphincter of Oddi contraction amplitude and duration were unaffected by octreotide. Subsequent cholecystokinin administration transiently reduced sphincter of Oddi basal pressure and contraction frequency. We conclude that octreotide significantly increases sphincter of Oddi basal pressure and contraction frequency. This effect is distinct from octreotide induction of migrating motor complex phase III activity, persists for a prolonged period, and is inhibited by cholecystokinin.     

Effects of ligand priming and multiple-dose injection on tissue uptake of 111In-pentetreotide in rats

In patients undergoing somatostatin receptor scintigraphy, treatment with octreotide (Sandostatin) is usually discontinued 24-48 h before and after injection with the radioligand 111In-pentetreotide ([111In-DTPA(O)]octreotide) (Octreoscan) because octreotide competes with radioligand for the same receptors. However, D?rr et al. and Soresi et al. reported improved visualization of carcinoid and small cell lung cancer lesions, respectively, during continued octreotide treatment. We found that intravenous administration of unlabeled octreotide to rats inhibited the binding of an optimal dose (0.5 microg) of 111In-pentetreotide to somatostatin receptors in pancreas and adrenals in a mass- and time-dependent way. Pretreatment with unlabeled octreotide never increased receptor binding of 111In-pentetreotide. Administration of 100 microg of octreotide decreased receptor-bound radioactivity if given simultaneously with or 10 or 20 min after injection of the radioligand, but had no effect if given 30 min after the radioligand. These findings indicate rapid processing of receptor-bound octreotide and suggest that octreotide treatment of patients undergoing 111In-pentetreotide scintigraphy may be reinitiated as soon as 1 h after radioligand administration.