Pancreatic lipase inhibitors: The road voyaged and successes.

Human pancreatic lipase (triacylglycerol acyl hydrolase EC3.1.1.3) is the most widely studied member of the human lipase superfamily related to carboxyl esterase. It is secreted from the acinar cell of pancreas and has strong preference for triacylglycerides over cholesterol esters, phospholipids, and galactolipids. Apart from the hydrolysis of triacylglycerides, pancreatic lipase may cause the hydrolysis of retinyl esters in vivo. So, it is very much evidenced that pancreatic lipase with its cofactor colipase has prominent role in efficient digestion of dietary fat. Hence, the modulation of human pancreatic lipase may represent a new insight in the discovery of a number of therapeutics that can inhibit the absorption of fat in body and can be used in obesity and other related metabolic disorders. Even, the only Food and drug administration (FDA) approved antiobesity drug, orlistat, is also an inhibitor of pancreatic lipase. This review summarizes studies about structure, mechanistic approach of pancreatic lipase enzyme while emphasizing on the various synthetic pancreatic lipase inhibitors with their structure activity relationship (SAR).

N-stearoyltyrosine dipotassium ameliorates high-fat diet-induced obesity in C57BL/6 mice.

N-stearoyltyrosine dipotassium (NST-2K) as a neuroprotective candidate is currently in preclinical studies in China. This study investigated the anti-obese effect of NST-2K in high-fat diet-induced obese (DIO) mice. The DIO mice were induced from male C57BL/6 mice by feeding high-fat diet for 11-weeks and treated orally with NST-2K for other 4 weeks. The treatments of DIO mice with NST-2K at 60 or 100 mg/kg/day suppressed the body weight gain, decreased both visceral fat weight and adipocyte size without influence on food intake. To evaluate the effect of NST-2K on lipid metabolism, lipid parameters and several key molecules in the plasma, liver, duodenum mucosa and adipose tissue were analyzed. NST-2K ameliorated the low-grade inflammation in liver, inhibited pancreatic lipase activity in duodenum mucosa, activated ß-oxidation system and reduced lipogenesis, thus suppressed lipid accumulation in the liver, reduced adipocyte size and improved lipid and carbohydrate metabolism. Overall, without influence on food intake, NST-2K ameliorated high-fat diet-induced obesity via suppressing liver inflammation, inhibiting dietary fat absorption, promoting lipolysis and reducing lipogenesis.

Long-term green tea extract supplementation does not affect fat absorption, resting energy expenditure, and body composition in adults.

BACKGROUND: Green tea (GT) extract may play a role in body weight regulation. Suggested mechanisms are decreased fat absorption and increased energy expenditure. OBJECTIVE: We examined whether GT supplementation for 12 wk has beneficial effects on weight control via a reduction in dietary lipid absorption as well as an increase in resting energy expenditure (REE). METHODS: Sixty Caucasian men and women [BMI (in kg/m²): 18-25 or >25; age: 18-50 y] were included in a randomized placebo-controlled study in which fecal energy content (FEC), fecal fat content (FFC), resting energy expenditure, respiratory quotient (RQ), body composition, and physical activity were measured twice (baseline vs. week 12). For 12 wk, subjects consumed either GT (>0.56 g/d epigallocatechin gallate + 0.28-0.45 g/d caffeine) or placebo capsules. Before the measurements, subjects recorded energy intake for 4 consecutive days and collected feces for 3 consecutive days. RESULTS: No significant differences between groups and no significant changes over time were observed for the measured variables. Overall means ± SDs were 7.2 ± 3.8 g/d, 6.1 ± 1.2 MJ/d, 67.3 ± 14.3 kg, and 29.8 ± 8.6% for FFC, REE, body weight, and body fat percentage, respectively. CONCLUSION: GT supplementation for 12 wk in 60 men and women did not have a significant effect on FEC, FFC, REE, RQ, and body composition.

DHA suppresses Prevotella intermedia lipopolysaccharide-induced production of proinflammatory mediators in murine macrophages.

Several reports have indicated that dietary intake of DHA is associated with lower prevalence of periodontitis. In the present study, we investigated the effect of DHA on the production of proinflammatory mediators in murine macrophage-like RAW264.7 cells stimulated with lipopolysaccharide (LPS) isolated from Prevotella intermedia, a pathogen implicated in inflammatory periodontal disease, and its mechanisms of action. LPS was isolated from lyophilised P. intermedia ATCC 25,611 cells using the standard hot-phenol-water protocol. Culture supernatants were collected and assayed for NO, IL-1ß and IL-6. Real-time PCR analysis was carried out to detect the expression of inducible NO synthase (iNOS), IL-1ß, IL-6 and haeme oxygenase-1 (HO-1) mRNA. Immunoblot analysis was carried out to quantify the expression of iNOS and HO-1 protein and concentrations of signalling proteins. DNA-binding activities of NF-κB subunits were determined using an ELISA-based assay kit. DHA significantly attenuated the production of NO, IL-1ß and IL-6 at both gene transcription and translation levels in P. intermedia LPS-activated RAW264.7 cells. DHA induced the expression of HO-1 in cells treated with P. intermedia LPS. Selective inhibition of HO-1 activity by tin protoporphyrin IX significantly mitigated the inhibitory effects of DHA on LPS-induced NO production. DHA significantly attenuated the phosphorylation of c-Jun N-terminal kinase induced by LPS. In addition, DHA suppressed the transcriptional activity of NF-κB by regulating the nuclear translocation and DNA-binding activity of NF-κB p50 subunit and inhibited the phosphorylation of signal transducer and activator of transcription 1. Further in vivo studies are needed to better evaluate the potential of DHA in humans as a therapeutic agent to treat periodontal disease.

Chronic high fat diet consumption impairs sensorimotor gating in mice.

Chronic intake of high fat diets (HFD) has been long recognized to induce neuronal adaptations and impair elementary cognitive functions. Yet, the consequences of chronic HFD consumption on central information processing remain elusive. The present study thus explored the impact of chronic HFD consumption on pre-attentive central information processing using the paradigm of prepulse inhibition (PPI) of the acoustic startle reflex in mice. Animals were fed an experimental diet with 60% of its calories derived from fat, and were compared to control low fat diet (LFD, 10% calories from fat) fed animals. A first experimental series demonstrated that adult mice exposed to chronic HFD throughout adolescent development displayed significant deficits in PPI compared to LFD-fed mice. Identical chronic HFD treatment further led to presynaptic dopaminergic abnormalities in the form of increased tyrosine hydroxylase density in the nucleus accumbens core and shell subregions. Moreover, we found that tyrosine hydroxylase density in the nucleus accumbens shell negatively correlated with the mean PPI scores, suggesting a potential contribution of the accumbal dopamine system to HFD-induced PPI deficits. This impression was further supported by an additional series of experiments showing that the HFD-induced attenuation of PPI can be mitigated by systemic administration of the dopamine receptor antagonist haloperidol. Finally, HFD feeding was sufficient to disrupt PPI when its exposure was restricted to the peripubertal period, whilst the same manipulation failed to affect PPI when limited to adulthood. In conclusion, our findings emphasize that pre-attentive information processing as assessed by the PPI paradigm is highly sensitive to nutritional factors in the form of chronic HFD consumption, especially when initiated during peripubertal maturation. It is likely that the disrupting effects of HFD on sensorimotor gating involve, at least in part, dopaminergic mechanisms.

Grape seed and skin extract prevents high-fat diet-induced brain lipotoxicity in rat.

Obesity is related to an elevated risk of dementia and the physiologic mechanisms whereby fat adversely affects the brain are poorly understood. The present investigation analyzed the effect of a high fat diet (HFD) on brain steatosis and oxidative stress and the intracellular mediators involved in signal transduction, as well as the protection offered by grape seed and skin extract (GSSE). HFD induced ectopic deposition of cholesterol and phospholipid but not triglyceride. Moreover brain lipotoxicity is linked to an oxidative stress characterized by increased lipoperoxidation and carbonylation, inhibition of glutathione peroxidase and superoxide dismutase activities, depletion of manganese and a concomitant increase in ionizable calcium and acetylcholinesterase activity. Importantly GSSE alleviated all the deleterious effects of HFD treatment. Altogether our data indicated that HFD could find some potential application in the treatment of manganism and that GSSE should be used as a safe anti-lipotoxic agent in the prevention and treatment of fat-induced brain injury.

The adenosine derivative 2',3',5'-tri-O-acetyl-N6-(3-hydroxylaniline) adenosine activates AMPK and regulates lipid metabolism in vitro and in vivo.

AIMS: Our overall objective was to investigate the effect of the adenosine derivative 2',3',5'-tri-O-acetyl-N6-(3-hydroxylaniline) adenosine (WS010117) on AMP-activated protein kinase (AMPK) activation and lipid metabolism and to also assess the underlying mechanisms involved in these processes. MAIN METHODS: HepG2 cells and hamsters fed a high-fat diet were used to test the effects of WS010117 on lipid metabolism. Western blots, chemical intervention, HPLC, SAMS peptide assay, (14)C-labelled acetate and palmitate assays, molecular docking assay and siRNA targeting the AMPK γ1 subunit were used to investigate the effect of WS010117 on AMPK activation as well as the underlying mechanism involved in this activation. KEY FINDINGS: WS010117 treatment resulted in the dose-dependent activation of AMPK in HepG2 cells, increasing lipid oxidation and decreasing lipid biosynthesis. In hamsters that were fed a high-fat diet, WS010117 treatment (1.5-6 mg/kg) significantly inhibited the increase in lipid accumulation. WS010117-induced AMPK activation was essentially abolished by treatment with compound C, and the addition of WS010117 did not alter the intracellular AMP:ATP ratio. In HeLa cells endogenously lacking LKB1, WS010117-mediated AMPK activation was not impaired, even following co-treatment with STO-609, a selective inhibitor of Ca(2+)/calmodulin-dependent protein kinase kinase (CaMKK). The results from the molecular docking assays and experiments targeting the AMPK γ1 subunit with siRNA indicated that WS010117 may activate AMPK by binding to and regulating the γ subunit of AMPK. SIGNIFICANCE: Our data indicate that WS010117 can regulate lipid metabolism through the activation of AMPK. WS010117 may activate AMPK by binding to and regulating the AMPK γ subunit.

Environmental enrichment ameliorated high-fat diet-induced Aß deposition and memory deficit in APP transgenic mice.

The pathogenesis of Alzheimer's disease (AD) is tightly associated with metabolic dysfunctions. In particular, a potential link between type 2 diabetes (T2DM) and AD has been suggested epidemiologically, clinically, and experimentally, and some studies have suggested that exercise or dietary intervention reduces risk of cognitive decline. However, there is little solid molecular evidence for the effective intervention of metabolic dysfunctions for prevention of AD. In the present study, we established the AD model mice with diabetic conditions through high-fat diet (HFD) to examine the effect of environmental enrichment (EE) on HFD-induced AD pathophysiology. Here, we demonstrated that HFD markedly deteriorated memory impairment and increased ß-amyloid (Aß) oligomers as well as Aß deposition in amyloid precursor protein (APP) transgenic mice, which was reversed by exposure to an enriched environment for 10 weeks, despite the continuation of HFD. These studies provide solid evidence that EE is a useful intervention to ameliorate behavioral changes and AD pathology in HFD-induced aggravation of AD symptoms in APP transgenic mice.

Ajoene, a stable garlic by-product, inhibits high fat diet-induced hepatic steatosis and oxidative injury through LKB1-dependent AMPK activation.

Hepatic steatosis, a hepatic component of metabolic syndrome, is common and may progress to steatohepatitis and cirrhosis. The liver X receptor-α (LXRα)-sterol regulatory element binding protein-1c (SREBP-1c) pathway plays a key role in hepatic steatosis. This study investigated the potential of ajoene, a stable garlic by-product, to inhibit high fat diet (HFD)-induced hepatic steatosis and the underlying mechanism. Ajoene treatment attenuated fat accumulation and induction of lipogenic genes in the liver of HFD-fed mice. Blood biochemical analyses and histopathologic examinations showed that ajoene prevented liver injury with the inhibition of oxidative stress, as evidenced by thiobarbituric acid reactive substances formation and nitrotyrosinylation. Moreover, ajoene treatment inhibited LXRα agonist (T0901317)-mediated SREBP-1c activation, and transactivation of the lipogenic target genes in hepatocytes. Ajoene was found to activate AMP-activated protein kinase (AMPK) via LKB1, responsible for the inhibition of p70 ribosomal S6 kinase-1 (S6K1). The ability of ajoene to repress T0901317-induced SREBP-1c expression was antagonized by inhibition of AMPK or activation of S6K1, supporting the role of these kinases in the antisteatotic effect. Our results demonstrate that ajoene has an effect of activating AMPK through LKB1 and inhibit S6K1 activity, contributing to the prevention of SREBP-1c-mediated hepatic lipogenesis via the inhibition of LXRα activity.

Clerodendron glandulosum.Coleb extract ameliorates high fat diet/fatty acid induced lipotoxicity in experimental models of non-alcoholic steatohepatitis.

This study evaluates the protective role of Clerodendron glandulosum.Coleb (CG) aqueous extract against high fat diet/fatty acid induced lipotoxicity in experimental models of non-alcoholic steatohepatitis (NASH). Supplementation of NASH mice with CG extract (1% and 3% in high fat diet for 16 weeks) prevented high fat diet induced elevation in liver enzymes, plasma and hepatic lipids, mitochondrial oxidative stress and compromised enzymatic and non-enzymatic antioxidant status and histopathological damage to hepatocytes. Furthermore, results from in vitro study indicates, addition of CG extract (20-200 µg/ml for 24h) to HepG2 cells minimizes oleic acid induced lipid accumulation, higher lipid peroxidation, cytotoxicity and reduced cell viability. These in vivo and in vitro studies suggest that CG extract has the potential of preventing high fat/fatty acid induced NASH.

Orexin A/hypocretin-1 selectively promotes motivation for positive reinforcers.

Orexin A/hypocretin-1 (oxA/hcrt-1) is known to be a modulator of dopamine-dependent neuronal activity and behaviors. However, the role of this system in driving motivated behaviors remains poorly understood. Here, we show that orexin/hypocretin receptor-1 (ox/hcrt-1R) signaling is important for motivation for highly salient, positive reinforcement. Blockade of ox/hcrt-1R selectively reduced work to self-administer cocaine or high fat food pellets. Moreover, oxA/hcrt-1 strengthened presynaptic glutamatergic inputs to the ventral tegmental area (VTA) only in cocaine or high fat self-administering rats. Finally, oxA/hcrt-1-mediated excitatory synaptic transmission onto VTA neurons was not potentiated following an arousing, aversive stimulus, suggesting that oxA/hcrt-1-mediated glutamatergic synaptic transmission was potentiated selectively with highly salient positive reinforcers. These experiments provide evidence for a selective role of oxA/hcrt-1 signaling in motivation for highly salient reinforcers and may represent a unique opportunity to design novel therapies that selectively reduce excessive drive to consume positive reinforcers of high salience.

Peroxisome proliferator-activated receptor-alpha activator fenofibrate prevents high-fat diet-induced renal lipotoxicity in spontaneously hypertensive rats.

We investigated the effects of a high-fat (HF) diet and peroxisome proliferator-activated receptor (PPAR)-alpha activation on the intrarenal lipotoxicity associated with the renin-angiotensin system (RAS) and oxidative stress using spontaneously hypertensive (SHR) rats. Male SHR and Wistar-Kyoto (WKY) rats at 8 weeks of age were fed either a normal-fat diet or an HF diet without or with fenofibrate treatment for 12 weeks. Severe intrarenal lipid accumulation was noted in the SHR rats fed an HF diet than in WYK rats fed an HF diet (P<0.05). This lipid accumulation was associated with a 70% decrease in renal PPARalpha expression in SHR rats, whereas an HF diet increased the expression of PPARalpha in WKY rats by threefold. An HF diet also activated intrarenal, not systemic, RAS and induced oxidative stress associated with reduced nitric oxide (NO) bioavailability. By contrast, fenofibrate attenuated weight gain, fat mass and insulin resistance. Fenofibrate recovered HF diet-induced decreases in intrarenal PPARalpha expression and fat accumulation, and abolished intrarenal RAS activation and oxidative stress in SHR-HF animals (P<0.01). These activities conferred protection against increased blood pressure (BP), glomerulosclerosis and renal inflammation. Intrarenal free fatty acid and triglyceride concentrations were positively correlated with angiotensin II (gamma=0.63, 0.36) and 24-h urinary 8-hydroxy-deoxyguanosine (gamma=0.36, 0.39), and negatively correlated with PPARalpha contents (gamma=-0.47, -0.44; P<0.05). An HF diet-induced lipotoxicity by depletion of intrarenal PPARalpha aggravated BP and renal inflammation as a result of intrarenal RAS activation and oxidative stress. Therefore, intervention with PPARalpha activators can effectively prevent diet-induced renal lipotoxicity in hypertensive rats.

Antagonism of T-type calcium channels inhibits high-fat diet-induced weight gain in mice.

The epidemics of obesity and metabolic disorders have well-recognized health and economic burdens. Pharmacologic treatments for these diseases remain unsatisfactory with respect to both efficacy and side-effect profiles. Here, we have identified a potential central role for T-type calcium channels in regulating body weight maintenance and sleep. Previously, it was shown that mice lacking CaV3.1 T-type calcium channels have altered sleep/wake activity. We found that these mice were also resistant to high-fat diet-induced weight gain, without changes in food intake or sensitivity to high-fat diet-induced disruptions of diurnal rhythm. Administration of a potent and selective antagonist of T-type calcium channels, TTA-A2, to normal-weight animals prior to the inactive phase acutely increased sleep, decreased body core temperature, and prevented high-fat diet-induced weight gain. Administration of TTA-A2 to obese rodents reduced body weight and fat mass while concurrently increasing lean muscle mass. These effects likely result from better alignment of diurnal feeding patterns with daily changes in circadian physiology and potentially an increased metabolic rate during the active phase. Together, these studies reveal what we believe to be a previously unknown role for T-type calcium channels in the regulation of sleep and weight maintenance and suggest the potential for a novel therapeutic approach to treating obesity.

Importance of the backbone conformation of (-)-ternatin in its fat-accumulation inhibitory activity against 3T3-L1 adipocytes.

Key relationships between the intramolecular H-bond-derived backbone conformation and the bioactivity of the novel fat-accumulation inhibitor (-)-ternatin are examined by analyses of the NMR spectroscopic data and CD spectra of designed analogues. The results reveal that the beta-turn structure of (-)-ternatin is responsible for its potent fat-accumulation inhibitory effect against 3T3-L1 murine adipocytes.

Reduction of dietary fat absorption by the novel gastrointestinal lipase inhibitor cetilistat in healthy volunteers.

AIMS: To assess the efficacy, pharmacodynamics, safety and tolerability of a range of doses of cetilistat, a novel inhibitor of gastrointestinal lipases, in healthy volunteers. METHODS: Three Phase I, randomized, placebo-controlled, parallel-group studies were conducted. Enrolled subjects in the three studies (n = 99) received a controlled calorie diet (total intake 2160 calories daily, 30% from fat). Twenty-four subjects were randomized to placebo and 66 were randomized to the following cetilistat doses: 50 mg three times daily [t.i.d. (n = 7)], 60 mg t.i.d. (n = 9), 100 mg t.i.d. (n = 7), 120 mg t.i.d. (n = 9), 150 mg t.i.d. (n = 16), 240 mg t.i.d. (n = 9) and 300 mg t.i.d. (n = 9). Nine subjects received the approved orlistat dose (120 mg t.i.d.). Treatment was for 5 days, with a 2-day run-in period and 1-day post-treatment follow-up. The primary outcome measure was daily faecal fat excretion. Secondary outcomes included plasma lipid levels, tolerability [gastrointestinal adverse events (AEs)] and safety. RESULTS: Cetilistat increased faecal fat excretion relative to baseline at all doses. Cetilistat was well tolerated, with gastrointestinal AEs the most common (51%). Steatorrhoea (oily stool) was more frequent in the orlistat group (4.11 events per subject) than in any cetilistat dose group (0.14-1.81 events per subject). Most AEs (98%) were mild or moderate in intensity. CONCLUSIONS: Cetilistat increased dietary fat excretion in healthy volunteers receiving a controlled calorie diet. Cetilistat was well tolerated at all doses examined and tolerability appeared to be improved relative to orlistat. Faecal fat excretion in the cetilistat groups was at least comparable to the orlistat 120 mg t.i.d. group.

Antiobesity therapy: emerging drugs and targets.

Obesity and its associated morbidities and mortalities are the effects of imbalance between energy intake and expenditure. The healthcare burden for the treatment of obesity is significantly high, due to increased risk of secondary chronic diseases such as hypertension and associated co-morbidities such as diabetes and cardiovascular disease. Lack of physical activity, high fat diets and sedentary life styles are major factors contributing to obesity. However, genetic predisposition and ethnicity are increasingly found to cause obesity. Till date, approved therapeutics have addressed excess energy intake by acting on central neural circuits that regulate feeding or on peripheral mechanisms to reduce nutrient absorption from the gut. These approaches have met with moderate success; and recently with safety concerns, leaving an unmet medical need for effective and safe pharmacotherapy for obesity thereby posing a significant challenge to pharmaceutical industry. Potential antiobesity drugs, which are being investigated by different companies, can be classified in 4 broad categories: 1) Agents that primarily decrease appetite through central action; 2) Agents that primarily increase metabolic rate or affect metabolism through peripheral action; 3) Agents that act on gastrointestinal tract; and 4) Agents that not only affect obesity but also overall Metabolic Syndrome. The current review will deal mainly with different molecules, which are under development for the above-mentioned targets and also their potential benefits and disadvantages.

Acute omega-3 fatty acid enrichment selectively reverses high-saturated fat feeding-induced insulin hypersecretion but does not improve peripheral insulin resistance.

In rats fed a high-saturated fat diet, replacement of a small percentage of total fatty acids with long-chain omega-3 fatty acids from fish oil for the duration of high-fat feeding prevents the development of insulin resistance. We investigated the effect of acute (24-h) modulation of dietary fat composition on glucose-stimulated insulin secretion (GSIS) in rats made insulin resistant by high-saturated fat feeding for 4 weeks. Insulin secretion after an intravenous glucose challenge was greatly increased by high-saturated fat feeding. Glucose tolerance was minimally perturbed, demonstrating insulin hypersecretion compensated for insulin resistance. The effect of high-saturated fat feeding to enhance GSIS was retained in perifused islets, such that glucose stimulus-secretion coupling was potentiated. Acute replacement of 7% of dietary fatty acids with long-chain omega-3 fatty acids reversed insulin hypersecretion in vivo, and the effect of long-term high-saturated fat feeding to enhance insulin secretion by perifused islets was also completely reversed. Although a hyperbolic relationship existed between insulin secretion and action in the high-saturated fat and control groups, lowered insulin secretion in the acute fish oil-supplemented group was not accompanied by improved insulin action, and glucose tolerance was adversely affected. Our studies are important because they demonstrate that hyperinsulinemia can be rapidly reversed via the dietary provision of small amounts of long-chain omega-3 fatty acids. However, this "insulin sparing" action of acute dietary long-chain omega-3 fatty acids occurs in the absence of an acute improvement in insulin sensitivity and therefore at the expense of maintenance of glucose tolerance.

Enterostatin inhibition of dietary fat intake is dependent on CCK-A receptors.

Enterostatin, a pentapeptide released from the exocrine pancreas and gastrointestinal tract, selectively inhibits fat intake through activation of an afferent vagal signaling pathway. This study investigated if the effects of enterostatin were mediated through a CCK-dependent pathway. The series of in vivo and in vitro experiments included studies of 1) the feeding effect of peripheral enterostatin on Otsuka Long Evans Tokushima Fatty (OLETF) rats lacking CCK-A receptors, 2) the effect of CCK-8S on the intake of a two-choice high-fat (HF)/low-fat (LF) diet, 3) the effects of peripheral or central injection of the CCK-A receptor antagonist lorglumide on the feeding inhibition induced by either central or peripheral enterostatin, and 4) the ability of enterostatin to displace CCK binding in a 3T3 cell line expressing CCK-A receptor gene and in rat brain sections. The results showed that OLTEF rats did not respond to enterostatin (300 microg/kg ip) in contrast to the 23% reduction in intake of HF diet in Long Evans Tokushima Otsuka (LETO) control rats. CCK (1 microg/kg ip) decreased the intake of the HF diet in a two-choice diet regime with a compensatory increase in intake of the LF diet. Peripheral injection of lorglumide (300 microg/kg) blocked the feeding inhibition induced by either near-celiac arterial or intracerebroventricular enterostatin, whereas intracerebroventricular lorglumide (5 nmol icv) only blocked the response to intracerebroventricular enterostatin but not to arterial enterostatin. Enterostatin did not bind on CCK-A receptors because neither enterostatin nor its analogs VPDPR and beta-casomorphin displaced [3H]L-364,718 from CCK-A receptors expressed in 3T3 cells or the binding of 125I-CCK-8S from rat brain sections. The data suggest that both the peripheral and central responses to enterostatin are mediated through or dependent on peripheral and central CCK-A receptors.