Octreotide enhances portal pressure reduction induced by propranolol in cirrhosis: a randomized, controlled trial

BACKGROUND: In vitro, octreotide potentiates vasoconstriction in isolated, preconstricted, mesenteric arterial vessels. In cirrhotic patients, portal pressure (HVPG) reduction induced by propranolol is partly due to splanchnic vasoconstriction. AIM: To evaluate HVPG effects of octreotide administration in cirrhotic patients receiving long-term propranolol. PATIENTS AND METHODS: A randomized, controlled trial. First study: a total of 28 patients were studied at baseline and 30 and 60 minutes after octreotide (200 mug) (N = 14) or placebo (N = 14) and then treated with propranolol for approximately 30 days (106 +/- 5 mg/day). Second study: after baseline evaluation patients received octreotide or placebo as they were assigned to in the first study and measurements repeated 30 and 60 minutes later. RESULTS: In the first study baseline HVPG was 18.7 +/- 0.9 mmHg and decreased to 17.1 +/- 1.1 mmHg and 17.1 +/- 1.0 mmHg (both P < 0.05 vs baseline) at 30 and 60 minutes after octreotide, respectively. Eight patients decreased their HVPG after octreotide. In the second study baseline HVPG was 15.6 +/- 1.3 mmHg (P < 0.01 vs baseline HVPG in first study) and decreased to 14.1 +/- 1.2 mmHg and 14.1 +/- 1.3 mmHg (25.7 +/- 5% lower than baseline HVPG in the first study, P < 0.01) (both P < 0.05 vs baseline) at 30 and 60 minutes after octreotide, respectively. Nine patients (2 responders/7 nonresponders to propranolol) decreased their HVPG after octreotide. Octreotide effects may be mediated by potentiation and additive mechanisms. CONCLUSIONS: Octreotide enhances HVPG reduction induced by propranolol in cirrhotic patients.     

Low doses of isosorbide mononitrate attenuate the postprandial increase in portal pressure in patients with cirrhosis

Postprandial hyperemia is associated with a significant increase in portal pressure in cirrhosis, which may contribute to progressive dilation and rupture of gastroesophageal varices. In cirrhosis, an insufficient hepatic production of nitric oxide (NO) may impair the expected hepatic vasodilatory response to increased blood flow, further exaggerating the postprandial increase in portal pressure. This study was aimed at investigating whether low doses of an oral NO donor might counteract the postprandial peak in portal pressure. Twenty-three portal hypertensive cirrhotics, 8 of them under propranolol therapy, were randomized to receive orally 5-isosorbide mononitrate (ISMN; 10 mg; n = 11) or placebo (n = 12) and a standard liquid meal 15 minutes later. Hepatic venous pressure gradient (HVPG), mean arterial pressure (MAP), and hepatic blood flow (HBF) were measured at baseline and 15, 30, and 45 minutes after a meal. ISMN significantly attenuated the postprandial increase in portal pressure as compared with placebo (peak HVPG increase: 2.4 +/- 1.4 mm Hg vs. 5.2 +/- 2.1 mm Hg, P =.002). Percentual increases in HBF were similar in both groups. MAP decreased slightly in ISMN group (-7.5% +/-.5%; P <.01 vs. baseline). These effects were also observed in patients on chronic propranolol therapy. In conclusion, hepatic NO supplementation by low doses of ISMN effectively reduces the postprandial increase of portal pressure in cirrhosis, with only a mild effect on arterial pressure. The same was observed in patients receiving propranolol. Our results suggest that therapeutic strategies based on selective hepatic NO delivery may improve the treatment of portal hypertension.     

Octreotide inhibits the meal-induced increases in the portal venous pressure of cirrhotic patients with portal hypertension: a double-blind, placebo-controlled study.

The aim of this study was to determine the effects of the long-acting somatostatin analog, octreotide, on portal venous pressure and collateral blood flow in cirrhotic patients with portal hypertension during fasting and postprandial states. In a double-blind, placebo-controlled study, we investigated the effects of octreotide on the hepatic venous pressures and azygos blood flow of 21 patients before and after a standard liquid meal containing 40 gm of protein in 250 ml. Octreotide significantly reduced azygos blood flow from a mean of 499 +/- 65 ml/min to a mean of 355 +/- 47 ml/min (p < 0.01), but it had no effect on the hepatic venous pressure gradient. The hepatic venous pressure gradient of patients in the placebo group increased significantly, from a fasting mean of 16.4 +/- 1.6 mm Hg to a mean of 20.0 +/- 1.7 mm Hg 30 min after the meal (p < 0.01). In a second protocol hepatic venous pressures were measured in 20 patients at 30-min intervals for 2 hr after ingestion of the mixed meal. Again the placebo group showed a significant increase in the hepatic venous pressure gradient 30 min after the meal (20.4 +/- 1.5 mm Hg vs. 18.2 +/- 1.2 mm Hg; p < 0.05), but the group receiving octreotide showed no significant changes during the 2 hr of observation. We conclude that octreotide significantly reduces azygos blood flow, with little effect on portal venous pressure, and that it appears to inhibit postprandial increases in portal pressure in cirrhotic patients with portal hypertension.     

Effects of different octreotide dosages on splanchnic hemodynamics and glucagon in patients with TIPS

OBJECTIVE: The aim of this study was to evaluate the hemodynamic effects of octreotide in patients treated with transjugular intrahepatic portosystemic stent shunt in relation to plasma levels of octreotide and glucagon and the correlation between portal pressure and noninvasive Doppler parameters. METHODS: In 15 fasting patients, we i.v. administered isotonic sodium chloride followed by octreotide 25 microg/h and 100 microg/h, each over 1 h. We measured portal pressure (PP) directly and portal vein blood flow velocity by Doppler ultrasound simultaneously and calculated portal vascular resistance (PVR) and portal venous flow (PVF). Blood samples were taken for glucagon and octreotide (mean +/- SE). RESULTS: Octreotide reduced PP (120': -7.7+/-2.2%, p < 0.01 vs baseline; 180': - 11.4+/-2.1%, p < 0.01 vs baseline) and PVF (120': -21.7+/-31.7%, p < 0.01 vs baseline; 180': -11.6+/-18.1%, p < 0.05 vs baseline). Glucagon decreased with the increase in octreotide levels and showed a correlation with the decrease in PP and with PVF. In patients with a high PVR, we found a close inverse correlation between PP and portal vein blood flow velocity (r = -0.83, p = 0.03) as well as Cl (r = 0.81, p = 0.05), whereas poor correlation was found in patients with low PVR. CONCLUSIONS: Octreotide caused a dose-related, moderate but sustained reduction in PP in patients with transjugular intrahepatic portosystemic stent shunt. PVR seems to be an important parameter that influences the efficacy of octreotide and the relation between PP and noninvasive Doppler parameters.     

双剂量奥曲肽对肝硬化门脉高压症断流术后患者血流动力学的影响

目的研究双剂量奥曲肽对肝硬化门脉高压症断流术后患者门脉压力、肝脏血流动力学影响。方法肝硬化门脉高压症断流术患者26例,随机分两组,术后24h开始用奥曲肽。A组12例,奥曲肽50μg／h;B组14例,奥曲肽25μg／h;胃网膜右静脉插管至门静脉主干,动态测定门脉压力;彩色超声多普勒测定门脉直径（PV）、门脉最大血流速度（PFVmax）、门脉平均血流速度（PFVmean）、肝动脉最大血流速度（HAVmax）、肝动脉最小血流速度（HAVmin）;计算门脉血流量参数（PFI）、肝动脉血流量参数（HAFI）。结果断流术后,两组患者门脉压力平均降幅15．4％,PFI降低（P〈0．05）;HAVmax、HAVmin、HAFI增加（P〈0．05）。用奥曲肽72h后,两组PFI、PFVmax、PFVmean降低（P〈0．05）;用药5min门脉压力降低,24h达高峰,门脉压力平均降幅20．6％。A组停药后48h内,门脉压力未见回升,平均降幅23．1％;B组停药后2h门脉压力有回升趋势,平均降幅11．6％;停药后24h、48h两组患者门脉压力比较差异有统计学意义（P〈0．01）。Logistic分析发现,PV、PFVmax、PFVmean、HAVmax、HAVmin与门脉压力无独立相关性。结论肝硬化门脉高压症患者行断流术后,门脉压力降低。双剂量奥曲肽均能明显降低门脉压力;停药后48h内,奥曲肽50μg／h组门脉压力未见回升。提示,临床用奥曲肽50μg/h对防止静脉曲张再出血更合理。     

Simvastatin enhances hepatic nitric oxide production and decreases the hepatic vascular tone in patients with cirrhosis

BACKGROUND & AIMS: In cirrhosis, an insufficient release of nitric oxide contributes to increased hepatic resistance and portal pressure and enhances the postprandial increase in portal pressure. We hypothesized that simvastatin, which enhances Akt-dependent endothelial nitric oxide synthase phosphorylation, may increase hepatic nitric oxide release and decrease hepatic resistance in patients with cirrhosis and portal hypertension. METHODS: In protocol 1, 13 patients had measurements of the hepatic venous pressure gradient, hepatic blood flow, mean arterial pressure, cardiac output, and nitric oxide products before and 30 and 60 minutes after 40 mg of simvastatin. In protocol 2, 17 patients were randomized to receive placebo or simvastatin (40 mg) 12 hours and 1 hour before the study. After baseline measurements of the hepatic venous pressure gradient, hepatic blood flow, and nitric oxide products, a standard liquid meal was given, and measurements were repeated at 15, 30, and 45 minutes. RESULTS: In protocol 1, acute simvastatin did not modify the hepatic venous pressure gradient but increased the hepatic blood flow (21% +/- 13% at 30 minutes; P = 0.01) and decreased hepatic sinusoidal resistance by 14% +/- 11% (P = 0.04). Nitric oxide product levels significantly increased in hepatic venous blood (from 31.4 +/- 12.3 nmol. mL(-1) to 35.8 +/- 10.7 nmol. mL(-1); P = 0.04), but not in peripheral blood. Systemic hemodynamics were not modified. In protocol 2, simvastatin pretreatment significantly attenuated the postprandial increase in hepatic venous pressure gradient (mean peak increase, 10% +/- 9% vs. 21% +/- 6% in placebo; P = 0.01). Hepatic blood flow increased similarly in the 2 groups. Hepatic nitric oxide products increased in the simvastatin group but not in the placebo group. CONCLUSIONS: Simvastatin administration increases the hepatosplanchnic output of nitric oxide products and decreases hepatic resistance in patients with cirrhosis.     

Double-blind investigation of the effects of propranolol and placebo on the pressure of esophageal varices in patients with portal hypertension

This study was aimed at investigating the effects of propranolol on esophageal variceal pressure in patients with portal hypertension. Variceal pressure was measured at endoscopy using a miniature pressure-sensitive gauge in 20 patients with portal hypertension. Measurements were obtained under baseline conditions and 20 min after double-blind administration of propranolol (0.15 mg/kg; n = 10) or an identical amount of placebo (normal saline, 0.3 ml/kg; n = 10). Under baseline conditions, variceal pressure was similar in propranolol and placebo groups (14.1 +/- 5 mm Hg vs. 14.9 +/- 6.6 mm Hg, respectively; not significant). Placebo had no significant effect on variceal pressure (baseline = 14.9 +/- 6.6 mm Hg; placebo = 15.5 +/- 6.6 mm Hg; not significant), and values after placebo administration were closely correlated with baseline values (r = 0.98; y = 1.1 + 0.97 x; p less than 0.0001). In contrast, propranolol caused a significant decrease in the pressure of esophageal varices (from 14.1 +/- 5 mm Hg to 11.3 +/- 4.4 mm Hg; p less than 0.0002). No significant changes in the size of esophageal varices were observed after propranolol or placebo administration. This study shows (a) the endoscopic pressure-gauge technique has a low variability and may be used to assess acute drug-induced changes in variceal pressure; and (b) propranolol causes significant decreases in variceal pressure in patients with portal hypertension and esophageal varices.     

Desensitization to the effects of intravenous octreotide in cirrhotic patients with portal hypertension

BACKGROUND & AIMS: Octreotide has been suggested for the treatment of variceal bleeding, but detailed dose-finding studies are not available. We performed a dose-finding study investigating the hemodynamic effects of several forms of intravenous octreotide administration. METHODS: Splanchnic hemodynamics and plasma glucagon levels were measured in 68 cirrhotics in baseline conditions and (1) after a double-blind intravenous injection of octreotide (50 microg [n = 9] or 500 microg [n = 8]) or placebo (n = 7); (2) after a 50-microg octreotide bolus followed by continuous infusion of 50 microg/h (n = 8), 250 microg/h (n = 8), or placebo (n = 6); (3) after repeated 50-microg injections of octreotide (n = 9) or placebo (n = 6) after an initial bolus (50 microg octreotide); and (4) after a placebo bolus and continuous octreotide infusion (50 microg/h; n = 7). RESULTS: Placebo caused no significant changes. Octreotide caused a marked and transient decrease in portal pressure and azygos blood flow and an increase in mean arterial pressure. These effects lasted only 5 minutes despite addition of continuous octreotide infusions. Repeated octreotide injections had shorter, less marked effects than the first bolus. A continuous octreotide infusion did not decrease portal pressure. Glucagon levels were markedly reduced by octreotide, but gradually returned to baseline despite continuous infusions or repeated injections of octreotide. CONCLUSIONS: Octreotide injection caused marked but transient reductions in portal pressure and azygos blood flow. Adding a continuous octreotide infusion neither maintained nor prolonged its effects. Repeated boluses caused significant tachyphylaxis. This rapid desensitization to the effects of octreotide may explain the divergent effects achieved with octreotide infusions in acute variceal bleeding.     

Octreotide blunts postprandial splanchnic hyperemia in cirrhotic patients: A double-blind randomized echo-doppler study

The effect of octreotide, a long-acting synthetic analog of somatostatin, on fasting and postprandial splanchnic hemodynamics was investigated in cirrhotic patients. Splanchnic hemodynamics were assessed using an echo-Doppler duplex system in a prospective, double-blind, placebo-controlled, crossover study performed on 2 separate days, 1 week apart, in 30 cirrhotic patients. Measurements of portal vein (PV) cross-sectional area (PVA) and mean velocity (PV-V), and of superior mesenteric artery (SMA) mean velocity (SMA-V) and pulsatility index (SMA-PI) (an index of vascular resistance) were performed at baseline, 30 minutes after octreotide (200 μg subcutaneously) or placebo administration, and 30 and 60 minutes after the ingestion of a liquid meal. In the fasted state, octreotide induced a significant decrease in PV-V (−7%) and in SMA-V (−10%) and an increase in PI (+16%). On the day of placebo administration, meal ingestion induced a significant increase in PV-V (+21%) and in SMA-V (+43%) and a decrease in PI (−21%). In contrast, meal ingestion on octreotide day induced significantly smaller increases in PV-V (+10%) and in SMAV (+18%) and a significantly smaller decrease in PI (−10%). Octreotide, although producing a mild reduction in PV-V and SMA-V in the fasted state, markedly blunts postprandial splanchnic hyperemia in cirrhotic patients.     

Water drinking as a treatment for orthostatic syndromes

PURPOSE: Water drinking increases blood pressure in a substantial proportion of patients who have severe orthostatic hypotension due to autonomic failure. We tested the hypothesis that water drinking can be used as a practical treatment for patients with orthostatic and postprandial hypotension, as well as those with orthostatic tachycardia. SUBJECTS AND METHODS: We studied the effect of drinking water on seated and standing blood pressure and heart rate in 11 patients who had severe orthostatic hypotension due to autonomic failure and in 9 patients who had orthostatic tachycardia due to idiopathic orthostatic intolerance. We also tested the effect of water drinking on postprandial hypotension in 7 patients who had autonomic failure. Patients drank 480 mL of tap water at room temperature in less than 5 minutes. RESULTS: In patients with autonomic failure, mean (+/- SD) blood pressure after 1 minute of standing was 83 +/- 6/53 +/- 3.4 mm Hg at baseline, which increased to 114 +/- 30/66 +/- 18 mm Hg (P <0.01) 35 minutes after drinking. After a meal, blood pressure decreased by 43 +/- 36/20 +/- 13 mm Hg without water drinking, compared with 22 +/- 10/12 +/- 5 mm Hg with drinking (P <0.001). In patients with idiopathic orthostatic intolerance, water drinking attenuated orthostatic tachycardia (123 +/- 23 beats per minute) at baseline to 108 +/- 21 beats per minute after water drinking ( P <0.001). CONCLUSION: Water drinking elicits a rapid pressor response in patients with autonomic failure and can be used to treat orthostatic and postprandial hypotension. Water drinking moderately reduces orthostatic tachycardia in patients with idiopathic orthostatic intolerance. Thus, water drinking may serve as an adjunctive treatment in patients with impaired orthostatic tolerance.     

Postprandial hypotension]

INTRODUCTION: A decrease in blood pressure (BP) 30 to 60 minutes after food ingestion is a physiologic and asymptomatic event, and is about 10 to 16 mm Hg in elderly subjects, but only 3 to 4 mm Hg in youths. PATIENTS AND METHODS: Sixteen women referred to our hospital with complains of lipothymia were studied. They were compared with a control population of 20 healthy subjects. Clinical, laboratory and electrocardiographic (12 leads and 24 hour "Holter" monitoring) evaluation, and 24 hour BP monitoring were performed. In the BP register, the period between the beginning and until 4 hours after the meal was analysed separately. RESULTS: The systolic and diastolic BP between the two populations was not significantly different (120.6 +/- 14.6 mm Hg and 76.5 +/- 8.9 mm Hg in the study group and 126.8 +/- 10.9 mm Hg and 77.8 +/- 7.2 mm Hg in the controls). The average of the mean BP was also not significantly different (78.7 +/- 11.7 mm Hg vs. 86.8 +/- 5 mm Hg, patients and controls). During the 4 hours after the meal there was a significant decrease (p < 0.01) in the average of the mean BP of the patients, which did not occur in the controls (65.4 +/- 7.3 mm Hg vs. 88.5 +/- 2.5 mm Hg, patients and controls). This postprandial decrease in BP correlated with the patients' symptomatology. CONCLUSIONS: Although physiologic in some individuals, the decrease in postprandial BP can be exaggerated and symptomatic. Outpatient BP monitoring can become a useful instrument in the evaluation of syncope/lipothymia.     

Acute hemodynamic effects of octreotide and terlipressin in patients with cirrhosis: a randomized comparison

BACKGROUND: Octreotide and terlipressin are widely used in acute variceal hemorrhage to reduce the bleeding rate. They purportedly act by mesenteric arterial vasoconstriction, thus reducing portal venous flow (PVF) and portal pressure. Little is known about the immediate-early hemodynamic effects of these drugs. AIM: To compare the acute hemodynamic effects of octreotide and terlipressin in patients with cirrhosis. PATIENTS: Forty-two cirrhotic patients with a history of variceal bleeding were randomized to receive either octreotide 100 microg intravenous bolus followed by a continuous infusion at 250 microg/h (n = 21), or terlipressin 2 mg intravenous bolus (n = 21). METHODS: Mean arterial pressure (MAP), heart rate (HR), hepatic venous pressure gradient (HVPG), and PVF, assessed by duplex Doppler ultrasonography, were measured before and at 1, 5, 10, 15, 20, and 25 min after the start of drug administration. RESULTS: Octreotide markedly decreased HVPG (-44.5 +/- 17.8%) and PVF (-30.6 +/- 13.6%) compared to the baseline at 1 min (p < 0.05). Thereafter, both variables rapidly returned toward the baseline, and by 5 min, no significant differences in HVPG (-7.1 +/- 28.9%) and PVF (10.2 +/- 26.2%) were noted. A similar transient effect on MAP and HR was observed. Terlipressin significantly decreased HVPG (-18.3 +/- 11.9%) and PVF (-32.6 +/- 10.5%) at 1 min (p < 0.05) and sustained these effects at all time points. The effects on arterial pressure and HR were also sustained. CONCLUSIONS: Octreotide only transiently reduced portal pressure and flow, whereas the effects of terlipressin were sustained. These results suggest that terlipressin may have more sustained hemodynamic effects in patients with bleeding varices.     

Mesenteric vasoconstriction triggers nitric oxide overproduction in the superior mesenteric artery of portal hypertensive rats

BACKGROUND & AIMS: Vasoconstriction of the superior mesenteric artery (SMA) is the earliest hemodynamic event occurring after partial portal vein ligation (PVL). We tested the hypothesis that this early vasoconstriction of the SMA may initiate eNOS up-regulation in PVL. METHODS: Portal hypertension with or without mesenteric vasoconstriction was induced by differentially calibrated stenosis of the portal vein (PVL-20G and PVL-18G, respectively). In a separate group of rats, mesenteric vasoconstriction was achieved by renal artery ligation. Sham-operated rats were used as controls. Effects of vasoconstriction of the SMA in PVL and RAL rats were evaluated by measuring perfusion pressure changes in isolated SMA beds in response to methoxamine, nitric oxide synthase activity, and eNOS protein expression. Mean arterial pressure, portal pressure, and SMA blood flow were measured by catheterization and Doppler flowmetry. SMA vascular resistance was calculated from arterial pressure, portal pressure, and SMA flow. RESULTS: There was a significant increase in SMA vascular resistance in PVL-20G (2.33 +/- 0.13 vs. 1.22 +/- 0.03 mm Hg/% flow; P < 0.05) and RAL (2.32 +/- 0.18 vs. 1.18 +/- 0.02 mm Hg/% flow; P < 0.05) but not in PVL-18G, showing mesenteric vasoconstriction in both PVL-20G and RAL groups. The mesenteric vasculature of PVL-20G and RAL animals showed hyporeactivity to methoxamine (P < 0.01). Whereas both PVL groups were portal hypertensive (P < 0.01), RAL rats were not. The SMA hyporeactivity of PVL-20G and RAL rats was corrected by N(G)()-monomethyl-L-arginine, and nitric oxide synthase enzyme activity was significantly higher in PVL-20G and RAL rats (P < 0.05). CONCLUSIONS: Mesenteric arterial vasoconstriction plays a triggering role in up-regulation of eNOS catalytic activity in the SMA of portal hypertensive rats.     

Spectral analysis of heart rate dynamics in elderly persons with postprandial hypotension.

Prior studies suggest that postprandial hypotension in elderly persons may be due to defective sympathetic nervous system activation. We examined autonomic control of heart rate (HR) after a meal using spectral analysis of HR data in 13 old (89 +/- 6 years) and 7 young (24 +/- 4 years) subjects. Total spectral power, an index of overall HR variability, was calculated for the frequency band between 0.01 and 0.40 Hz. Relatively low-frequency power, associated with sympathetic nervous system and baroreflex activation, was calculated for the 0.01 to 0.15 Hz band. High-frequency power, representing parasympathetic influences on HR, was calculated for the 0.15 to 0.40 Hz band. Mean arterial blood pressure declined 27 +/- 8 mm Hg by 60 minutes after the meal in elderly subjects, compared with 9 +/- 8 mm Hg in young subjects (p less than or equal to 0.0001, young vs old). The mean change in low-frequency HR power from 30 to 50 minutes after the meal was +19.4 +/- 25.3 U in young subjects versus -0.1 +/- 1.5 U in old subjects (p less than or equal to 0.02). Mean change in total power was also greater in young (19.0 +/- 26.6 U) subjects compared with old subjects (0.0 +/- 1.6 U, p greater than or equal to 0.02). Mean ratio of low:high-frequency power increased 3.1 +/- 3.3 U in young subjects vs 0.5 +/- 2.7 U in old subjects (p less than or equal to 0.01). The increase in low-frequency HR power and in the low:high frequency band ratio in young subjects is consistent with sympathetic activation in the postprandial period.(ABSTRACT TRUNCATED AT 250 WORDS)     

Synthetic somatostatin analog (octreotide) suppresses daytime growth hormone secretion equivalently in young and older men: preserved pituitary responsiveness to somatostatin's inhibition in aging

OBJECTIVE: To gain greater insight into the mechanisms controlling the low daytime rate of growth hormone (GH) secretion in older men. DESIGN: We conducted a randomized, controlled study of GH secretion during inhibition by octreotide, a somatostatin analog. PARTICIPANTS: Nine young (35-44 years) and ten older (62-79 years) healthy men participated. INTERVENTION: Octreotide versus nothing, while subjects were on a standardized diet. MEASUREMENTS: All subjects were assessed on two separate occasions: baseline and at time of the intervention of octreotide (100 microg subcutaneously); the order of the intervention was randomly assigned. Octreotide was administered at 8:00 a.m. Venous sampling was performed every 10 minutes for 8 hours (8:30 a.m. to 4:30 p.m.). To estimate the joint parameters of pulsatile and basal (between secretory pulses) GH secretion, we used an ultrasensitive chemiluminescence-based GH assay and multiparameter deconvolution analysis. RESULTS: Compared with baseline, octreotide markedly reduced mean (8-hour) serum GH concentrations in both young (0.585+/-0.255 microg/L vs 0.070+/-0.029 microg/L; P = .008) and older (0.397+/-0.107 microg/L vs 0.087+/-0.027 microg/L; P = 0.005) men. In younger men, octreotide decreased the serum GH concentration primarily by suppressing the mass of GH released per secretory pulse (2.4+/-0.9 microg/L vs 1.0+/-.7 microg/L; P = .015) and the interpulse (basal) rate of GH release (0.0014+/-0.0003 microg/L/min vs 0.0006+/-0.0002 microg/L/min; P = .051). In older men, octreotide also restrained the mass of GH per secretory pulse (1.5+/-0.4 microg/L vs 0.4+/-0.1 microg/L; P = .028) and lowered basal GH release (0.0014+/-0.0003 microg/L/min vs 0.0004+/-0.0001 microg/L/min; P = .007). There were no significant differences when the older men were compared with the young controls. CONCLUSIONS: Our data suggest that the daytime relative GH deficiency seen in older men is not a result of excessive pituitary susceptibility to the inhibitory capabilities of somatostatin, but more likely reflects impoverished endogenous GHRH drive and/or heightened release of brain somatostatin.     

Acute and chronic hemodynamic effects of propranolol in unselected cirrhotic patients

Different and contradictory results concerning the use of propranolol in the treatment of portal hypertension have been reported. This study was designed to investigate the hemodynamic effects of short- and long-term administration of propranolol in portal hypertensive patients. Portal pressure, cardiac index, heart rate and blood pressure were obtained in 18 unselected alcoholic cirrhotic patients with esophageal varices before and 60 min after the oral administration of 40 mg propranolol and again after 106 +/- 35 days of continuous oral administration (mean dose = 158 +/- 63 mg per day). Baseline portal pressure was 21.7 +/- 7.2 mm Hg. It decreased after 60 min to 17.2 +/- 5.5 mm Hg (p less than 0.01) and after long-term administration of propranolol to 16.1 +/- 5.7 mm Hg (p less than 0.01). No decrease in portal pressure was noted in 9 of 18 (50%) patients after acute administration and 5 of 17 (30%) patients after long-term administration. Baseline cardiac index was 5.1 +/- 1.2 liters X min-1 X m-2. It decreased after 60 min to 3.9 +/- 1.4 liters X min-1 X m-2 (p less than 0.01) and to 3.6 +/- 1.0 liters X min-1 X m-2 after long-term administration (p less than 0.001). Baseline heart rate was 85 +/- 11 beats per min. It decreased after 60 min to 75 +/- 9 (p less than 0.001) and after long-term administration to 62 +/- 6 (p less than 0.001) beats per min. Baseline mean arterial pressure was 108 +/- 11 Hg. It decreased after 60 min to 97 +/- 14 mm Hg (p less than 0.01) and after long-term administration to 103 +/- 14 mm Hg (not statistically significant).(ABSTRACT TRUNCATED AT 250 WORDS)     

Gastric emptying of liquids and solids in the portal hypertensive rat

The effects of portal hypertension on gastric motor function were investigated using the rat staged portal vein ligation model. Gastric emptying of liquids and solids was studied separately following meals labeled with 51Cr or 99Tc by whole stomach scintillation counting. Portal hypertension was consistently established in experimental rats (splenic pulp pressure: mean +/- SEM, portal hypertension versus control, 16.8 +/- 0.7 vs 11.8 +/- 0.7 mm Hg, P less than 0.0001). Although liquids were emptied in an exponential manner and solids in a linear fashion, gastric emptying of both meals was more rapid in the experimental rats. Ten minutes after the liquid meal, more than 50% of the meal had emptied from the stomachs of portal hypertensive rats while only one third of the meal had cleared in the control group (P less than 0.02). Gastric emptying of the solid meal was significantly accelerated in experimental rats at 60 and 120 min (percent meal remaining: portal hypertension versus control, 41.9 +/- 4.0 vs 55.4 +/- 3.5 and 21.5 +/- 4.9 vs 32.6 +/- 4.3, P less than 0.05). Stomachs of portal hypertensive animals were heavier (P less than 0.009) and histologic examination revealed submucosal edema. Thus, a possible mechanism of the disrupted gastric motor function in portal hypertension is decreased gastric wall compliance secondary to edema.     

Octreotide ameliorates the increase in collateral blood flow during postprandial hyperemia in portal hypertensive rats

BACKGROUND/AIMS: The aims of this study were to examine, in a conscious rat model of portal hypertension, the effect of postprandial splanchnic hyperemia on collateral blood flow and to determine whether octreotide has an effect on postprandial collateral flow changes. METHODS: In rats with portal vein ligation, pulsed-Doppler flowmeters were implanted chronically around the splenorenal venous shunt (SRS), which is the main spontaneous collateral vessel in the portal hypertensive rat and around the superior mesenteric artery (SMA). Changes in flow after a standard liquid meal gavage and after the administration of octreotide were examined in the rat under unanesthetized and unrestricted conditions. RESULTS: SRS flow increased significantly after gavage with a standard liquid meal (10.6+/-2.9%) compared to orogastric intubation alone (-6.5+/-2.1%) (P<0.01). Similar flow changes were observed in the SMA after liquid meal gavage. The subcutaneous administration of octreotide at a dose of 400 g/kg reduces basal SRS flow (-19.5+/-2.3%) and significantly attenuated the change in SRS flow after liquid meal gavage (-8.1+/-2.9%) compared to animals that received placebo (3.6+/-4.1% and 27.8+/-7.6%, respectively) (P<0.05). CONCLUSION: These results demonstrate that, in an experimental model of prehepatic portal hypertension, postprandial splanchnic hyperemia results in an increase in collateral flow that can be ameliorated with the use of octreotide.     

Octreotide therapy of pediatric hypothalamic obesity: a double-blind,placebo-controlled trial

Hypothalamic obesity is a devastating complication in children surviving brain tumors and/or cranial irradiation. These subjects are thought to exhibit autonomic dysregulation of the beta-cell, with insulin hypersecretion in response to oral glucose tolerance testing (OGTT). We report the results of a randomized, double-blind, placebo-controlled trial of octreotide therapy for pediatric hypothalamic obesity. Eighteen subjects [weight, 100.6 +/- 5.6 kg; body mass index (BMI), 37.1 +/- 1.3 kg/m(2)] received octreotide (5-15 microg/kg x d s.c.) or placebo for 6 months. With octreotide, Delta weight (mean +/- SEM) was +1.6 +/- 0.6 vs. +9.1 +/- 1.7 kg for placebo (P < 0.001). Delta BMI was -0.2 +/- 0.2 vs. +2.2 +/- 0.5 kg/m(2), respectively (P < 0.001). OGTT documented Delta insulin response (peak - basal) of -417 +/- 304 pM after octreotide vs. +216 +/- 215 pM after placebo (P = 0.034). Improvement in physical activity by parent report was noted with octreotide, but not placebo (P = 0.03). For the octreotide group, changes in quality of life positively correlated with changes in insulin response (P = 0.041). Complications and adverse events were mild and self-limited. These data demonstrate the beneficial effects of octreotide in pediatric hypothalamic obesity. Octreotide suppressed insulin, and stabilized weight and BMI. Improved quality of life correlated with the degree of insulin suppression. Octreotide was safe and well tolerated.     

Hemodynamic response to exercise after propranolol in patients with mitral stenosis.

Hemodynamic response to exercise before and 10 minutes after propranolol (5 mg intravenously) was studied in 10 young patients with pure mitral stenosis who had normal sinus rhythm and no cardiac failure. After propranolol the mean heart rate and cardiac index at rest were lower than during the control state (respectively, 95 +/- 4 versus 82 +/- 3 beats/min, P less than 0.005; 3.4 +/- 0.2 versus 2.8 +/- 0.1 liters/min per m2, P less than 0.025). As a result, the mean pulmonary wedge pressure and mean mitral valve gradient at rest were lower (respectively, 22 +/- 2 versus 18 +/- 2 mm Hg, P less than 0.005; 24 +/- 2 versus 17 +/- 2 mm Hg, P less than 0.001). During exercise after propranolol the values of pulmonary wedge pressure and mitral valve gradient were lower than control values during exercise (respectively, 39 +/- 3 versus 30 +/- 2 mm Hg, P less than 0.005; 44 +/- 3 versus 32 +/- 3 mm Hg, P less than 0.005), again because of the lower heart rate and cardiac index (130 +/- 6 versus 104 +/- 6 beats/min, P less than 0.001; 4.6 +/- 3 versus 3.7 +/- 2 liters/min per m2, P less than 0.01). Left ventricular end-diastolic pressure and stroke index showed no significant changes. Thus, propranolol may benefit patients with pure mitral stenosis with sinus rhythm and no cardiac failure whose symptoms occur during those reversible conditions characterized by an increase in heart rate or cardiac output, or both.