Tolerance development in cow's milk-allergic infants receiving amino acid-based formula: A randomized controlled trial.

BACKGROUND: Tolerance development is an important clinical outcome for infants with cow's milk allergy. OBJECTIVE: This multicenter, prospective, randomized, double-blind, controlled clinical study (NTR3725) evaluated tolerance development to cow's milk (CM) and safety of an amino acid-based formula (AAF) including synbiotics (AAF-S) comprising prebiotic oligosaccharides (oligofructose, inulin) and probiotic Bifidobacterium breve M-16V in infants with confirmed IgE-mediated CM allergy. METHODS: Subjects aged ≤13 months with IgE-mediated CM allergy were randomized to receive AAF-S (n = 80) or AAF (n = 89) for 12 months. Stratification was based on CM skin prick test wheal size and study site. After 12 and 24 months, CM tolerance was evaluated by double-blind, placebo-controlled food challenge. A logistic regression model used the all-subjects randomized data set. RESULTS: At baseline, mean ± SD age was 9.36 ± 2.53 months. At 12 and 24 months, respectively, 49% and 62% of subjects were CM tolerant (AAF-S 45% and 64%; AAF 52% and 59%), and not differ significantly between groups. During the 12-month intervention, the number of subjects reporting at least 1 adverse event did not significantly differ between groups; however, fewer subjects required hospitalization due to serious adverse events categorized as infections in the AAF-S versus AAF group (9% vs 20%; P = .036). CONCLUSIONS: After 12 and 24 months, CM tolerance was not different between groups and was in line with natural outgrowth. Results suggest that during the intervention, fewer subjects receiving AAF-S required hospitalization due to infections.

A synbiotic-containing amino-acid-based formula improves gut microbiota in non-IgE-mediated allergic infants.

BackgroundPrebiotics and probiotics (synbiotics) can modify gut microbiota and have potential in allergy management when combined with amino-acid-based formula (AAF) for infants with cow's milk allergy (CMA).MethodsThis multicenter, double-blind, randomized controlled trial investigated the effects of an AAF-including synbiotic blend on percentages of bifidobacteria and Eubacterium rectale/Clostridium coccoides group (ER/CC) in feces from infants with suspected non-IgE-mediated CMA. Feces from age-matched healthy breastfed infants were used as reference (healthy breastfed reference (HBR)) for primary outcomes. The CMA subjects were randomized and received test or control formula for 8 weeks. Test formula was a hypoallergenic, nutritionally complete AAF including a prebiotic blend of fructo-oligosaccharides and the probiotic strain Bifidobacterium breve M-16V. Control formula was AAF without synbiotics.ResultsA total of 35 (test) and 36 (control) subjects were randomized; HBR included 51 infants. At week 8, the median percentage of bifidobacteria was higher in the test group than in the control group (35.4% vs. 9.7%, respectively; P<0.001), whereas ER/CC was lower (9.5% vs. 24.2%, respectively; P<0.001). HBR levels of bifidobacteria and ER/CC were 55% and 6.5%, respectively.ConclusionAAF including specific synbiotics, which results in levels of bifidobacteria and ER/CC approximating levels in the HBR group, improves the fecal microbiota of infants with suspected non-IgE-mediated CMA.

Esophageal and Small Intestinal Mucosal Integrity in Eosinophilic Esophagitis and Response to an Elemental Diet.

OBJECTIVES: The esophageal mucosal integrity is impaired in eosinophilic esophagitis (EoE) and it has been suggested that the duodenal permeability is increased. The absence of food allergens may restore the integrity. The aims of this study were to assess duodenal permeability in EoE and to evaluate the effect of an elemental diet on the esophageal and duodenal integrity. METHODS: In this prospective study 17 adult EoE patients and 8 healthy controls (HC) were included. Esophageal biopsy specimens were sampled before and after 4 weeks of elemental diet to measure eosinophil counts and gene expression of tight junction and barrier integrity proteins. Esophageal and duodenal impedance were measured by electrical tissue impedance spectroscopy and Ussing chambers were used to measure transepithelial resistance (TER) and transepithelial molecule flux. Small intestinal permeability was measured using a test, measuring lactulose/mannitol (L/M) ratios. RESULTS: In EoE patients, the esophageal but not the duodenal integrity was impaired, compared with HC. We observed no significant difference between L/M ratios of HC and EoE patients. After diet, eosinophil counts decreased significantly, which was paralleled by normalization of esophageal impedance and transepithelial molecule flux. The esophageal TER improved significantly, but did not reach values seen in HC. Esophageal expression of genes encoding for barrier integrity proteins filaggrin and desmoglein-1 was impaired at baseline and restored after diet. CONCLUSIONS: An elemental diet restores esophageal integrity, suggesting that it is at least partly secondary to allergen exposure. Duodenal integrity seems not to be affected in EoE, and possibly plays a minor role in its pathophysiology.

Mineral Intake and Status of Cow's Milk Allergic Infants Consuming an Amino Acid-based Formula.

Data on the mineral status of infants with cow's milk allergy (CMA) consuming an amino acid-based formula (AAF) have not been published. The present study aims to assess mineral status of term infants age 0 to 8 months diagnosed with CMA receiving an AAF for 16 weeks. Serum concentrations of calcium, phosphorus, chloride, sodium, potassium, magnesium, and ferritin were determined in 82 subjects at baseline and in 66 subjects after 16 weeks on AAF using standard methods and evaluated against age-specific reference ranges. In addition to this, individual estimated energy and mineral intakes were compared to Adequate Intakes defined by the European Food Safety Authority and the US Institute of Medicine. The results of this study show that the AAF was effective in providing an adequate mineral status in infants with CMA. The vast majority of infants aged 0 to 6 months (formula only) and aged 6 to 12 months (formula and complementary foods) had adequate mineral intakes.

Synbiotics-supplemented amino acid-based formula supports adequate growth in cow's milk allergic infants.

BACKGROUND: Children with cow's milk allergy (CMA) are at risk for inadequate nutritional intake and growth. Dietary management of CMA, therefore, requires diets that are not only hypoallergenic but also support adequate growth in this population. This study assessed growth of CMA infants when using a new amino acid-based formula (AAF) with prebiotics and probiotics (synbiotics) and evaluated its safety in the intended population. METHODS: In a prospective, randomized, double-blind controlled study, full-term infants with diagnosed CMA received either an AAF (control; n = 56) or AAF with synbiotics (oligofructose, long-chain inulin, acidic oligosaccharides, Bifidobacterium breve M-16V) (test; n = 54) for 16 wk. Primary outcome was growth, measured as weight, length and head circumference. Secondary outcomes included allergic symptoms and stool characteristics. RESULTS: Average age (±SD) of infants at inclusion was 4.5 ± 2.4 months. Both formulas equally supported growth according to WHO 2006 growth charts and resulted in similar increases of weight, length and head circumference. At week 16, differences (90% CI) in Z-scores (test-control) were as follows: weight 0.147 (-0.10; 0.39, p = 0.32), length -0.299 (-0.69; 0.09, p = 0.21) and head circumference 0.152 (-0.15; 0.45, p = 0.40). Weight-for-age and length-for-age Z-scores were not significantly different between the test and control groups. Both formulas were well tolerated and reduced allergic symptoms; the number of adverse events was not different between the groups. CONCLUSIONS: This is the first study that shows that an AAF with a specific synbiotic blend, suitable for CMA infants, supports normal growth and growth similar to the AAF without synbiotics. This clinical trial is registered as NCT00664768.

Effects on growth and tolerance and hypoallergenicity of an amino acid-based formula with synbiotics.

BACKGROUND: To evaluate the effects of an amino acid-based formula (AAF) with synbiotics on growth and tolerance in healthy infants. The hypoallergenicity of this AAF with synbiotics was evaluated in subjects with cow's milk allergy (CMA). METHODS: Study 1: 115 full-term, healthy infants randomly received an AAF with synbiotics or a commercially available AAF for 16 wk. Subjects' weight, length, and head circumference were primary outcome measures. Stool characteristics and gastrointestinal (GI) symptoms were secondary outcome measures. Clinical examinations, dietary intake, clinical laboratory results, and adverse events were recorded. Study 2: hypoallergenicity of the AAF with synbiotics was evaluated in 30 infants and children with immunoglobulin E (IgE)-mediated CMA using a double-blind, placebo-controlled food challenge, and a 7-d feeding period. RESULTS: Study 1: comparable results in growth parameters and tolerance were observed for both groups. Minimal differences were observed in stool characteristics and GI symptoms throughout the study. Study 2: all 30 subjects with IgE-mediated CMA completed the study with no allergic reactions detected to challenges. CONCLUSION: These studies demonstrate that an AAF with synbiotics is safe and well tolerated and promotes normal growth when fed to healthy full-term infants as the sole source of nutrition and is hypoallergenic in subjects with CMA.

Obesity in pregnancy: implications for the mother and lifelong health of the child. A consensus statement.

Obesity among pregnant women is becoming one of the most important women's health issues. Obesity is associated with increased risk of almost all pregnancy complications: gestational hypertension, preeclampsia, gestational diabetes mellitus, delivery of large-for-GA infants, and higher incidence of congenital defects all occur more frequently than in women with a normal BMI. Evidence shows that a child of an obese mother may suffer from exposure to a suboptimal in utero environment and that early life adversities may extend into adulthood. In September 2009, ILSI Europe convened a workshop with multidisciplinary expertise to review practices and science base of health and nutrition of obese pregnant women, with focus on the long-term health of the child. The consensus viewpoint of the workshop identified gaps and gave recommendations for future research on gestational weight gain, gestational diabetes, and research methodologies. The evidence available on short- and long-term health impact for mother and child currently favors actions directed at controlling prepregnancy weight and preventing obesity in women of reproductive ages. More randomized controlled trials are needed to evaluate the effects of nutritional and behavioral interventions in pregnancy outcomes. Moreover, suggestions that maternal obesity may transfer obesity risk to child through non-Mendelian (e.g. epigenetic) mechanisms require more long-term investigation.

The Habitual Diet of Dutch Adult Patients with Eosinophilic Esophagitis Has Pro-Inflammatory Properties and Low Diet Quality Scores.

We determined the nutritional adequacy and overall quality of the diets of adult patients with eosinophilic esophagitis (EoE). Dietary intakes stratified by sex and age were compared to Dietary Reference Values (DRV). Overall diet quality was assessed by two independent Diet-Quality-Indices scores, the PANDiet and DHD-index, and compared to age- and gender-matched subjects from the general population. Lastly, food and nutrient intakes of EoE patients were compared to intakes of the general population. Saturated fat intake was significantly higher and dietary fiber intake significantly lower than the DRV in both males and females. In males, the DRV were not reached for potassium, magnesium, selenium, and vitamins A and D. In females, the DRV were not reached for iron, sodium, potassium, selenium, and vitamins A, B2, C and D. EoE patients had a significantly lower PANDiet and DHD-index compared to the general population, although the relative intake (per 1000 kcal) of vegetables/fruits/olives was significantly higher (yet still up to 65% below the recommended daily amounts) and alcohol intake was significantly lower compared to the general Dutch population. In conclusion, the composition of the habitual diet of adult EoE patients has several pro-inflammatory and thus unfavorable immunomodulatory properties, just as the general Dutch population, and EoE patients had lower overall diet quality scores than the general population. Due to the observational character of this study, further research is needed to explore whether this contributes to the development and progression of EoE.

A free amino acid-based diet partially prevents symptoms of cow's milk allergy in mice after oral sensitization with whey.

BACKGROUND: Amino acid-based formulas (AAFs) are used for the dietary management of cow's milk allergy (CMA). Whether AAFs have the potential to prevent the development and/or symptoms of CMA is not known. OBJECTIVE: The present study evaluated the preventive effects of an amino acid (AA)-based diet on allergic sensitization and symptoms of CMA in mice and aimed to provide insight into the underlying mechanism. METHODS: C3H/HeOuJ mice were sensitized with whey protein or with phosphate-buffered saline as sham-sensitized control. Starting 2 weeks before sensitization, mice were fed with either a protein-based diet or an AA-based diet with an AA composition based on that of the AAF Neocate, a commercially available AAF prescribed for the dietary management of CMA. Upon challenge, allergic symptoms, mast cell degranulation, whey-specific immunoglobulin levels, and FoxP3+ cell counts in jejunum sections were assessed. RESULTS: Compared to mice fed with the protein-based diet, AA-fed mice had significantly lower acute allergic skin responses. Moreover, the AA-based diet prevented the whey-induced symptoms of anaphylaxis and drop in body temperature. Whereas the AA-based diet had no effect on the levels of serum IgE and mucosal mast cell protease-1 (mMCP-1), AA-fed mice had significantly lower serum IgG2a levels and tended to have lower IgG1 levels (P = .076). In addition, the AA-based diet prevented the whey-induced decrease in FoxP3+ cells. In sham-sensitized mice, no differences between the two diets were observed in any of the tested parameters. CONCLUSION: This study demonstrates that an AA-based diet can at least partially prevent allergic symptoms of CMA in mice. Differences in FoxP3+ cell counts and serum levels of IgG2a and IgG1 may suggest enhanced anti-inflammatory and tolerizing capacities in AA-fed mice. This, combined with the absence of effects in sham-sensitized mice indicates that AAFs for the prevention of food allergies may be an interesting concept that warrants further research.

Effects of sucrose on salivary flow and composition: differences between real and sham intake.

Human saliva contains numerous salivary components that are fundamental for a healthy oral environment and the oral processing of foods. To study a possible differential influence of orosensory stimulation and metabolic activation on salivary composition, human parotid salivary flow, pH, A(280), and alpha-amylase activity were measured before, during and after real or sham (sip-and-spit) sucrose intakes. Variations in these salivary characteristics were related to perceived satiety. Sucrose, as either real or sham intake, increased salivary flow and pH and decreased A(280) before returning to pre-intake levels. Increased salivation was dependent on the sucrose concentration and was accompanied with a higher pH and lower A(280). After sucrose ingestion, the salivary alpha-amylase activity increased, while no increase occurred after sham sucrose intake. Similarly, rated satiety increased with real but not by sham sucrose intake. This indicated that salivary alpha-amylase is associated with perceived satiety controlled by caloric perception downstream of the oral cavity.

A specific synbiotic-containing amino acid-based formula in dietary management of cow's milk allergy: a randomized controlled trial.

BACKGROUND: Here we report follow-up data from a double-blind, randomized, controlled multicenter trial, which investigated fecal microbiota changes with a new amino acid-based formula (AAF) including synbiotics in infants with non-immunoglobulin E (IgE)-mediated cow's milk allergy (CMA). METHODS: Subjects were randomized to receive test product (AAF including fructo-oligosaccharides and Bifidobacterium breve M-16V) or control product (AAF) for 8 weeks, after which infants could continue study product until 26 weeks. Fecal percentages of bifidobacteria and Eubacterium rectale/Clostridium coccoides group (ER/CC) were assessed at 0, 8, 12, and 26 weeks. Additional endpoints included stool markers of gut immune status, clinical symptoms, and safety assessments including adverse events and medication use. RESULTS: The trial included 35 test subjects, 36 controls, and 51 in the healthy reference group. Study product was continued by 86% and 92% of test and control subjects between week 8-12, and by 71% and 80%, respectively until week 26. At week 26 median percentages of bifidobacteria were significantly higher in test than control [47.0% vs. 11.8% (p < 0.001)], whereas percentages of ER/CC were significantly lower [(13.7% vs. 23.6% (p = 0.003)]. Safety parameters were similar between groups. Interestingly use of dermatological medication and reported ear infections were lower in test versus control, p = 0.019 and 0.011, respectively. Baseline clinical symptoms and stool markers were mild (but persistent) and low, respectively. Symptoms reduced towards lowest score in both groups. CONCLUSION: Beneficial effects of this AAF including specific synbiotics on microbiota composition were observed over 26 weeks, and shown suitable for dietary management of infants with non-IgE-mediated CMA.Trial Registration NTR3979.

A specific synbiotic-containing amino acid-based formula restores gut microbiota in non-IgE mediated cow's milk allergic infants: a randomized controlled trial.

BACKGROUND: Altered gut microbiota is implicated in cow's milk allergy (CMA) and differs markedly from healthy, breastfed infants. Infants who suffer from severe CMA often rely on cow's milk protein avoidance and, when breastfeeding is not possible, on specialised infant formulas such as amino-acid based formulas (AAF). Herein, we report the effects of an AAF including specific synbiotics on oral and gastrointestinal microbiota of infants with non-IgE mediated CMA with reference to healthy, breastfed infants. METHODS: In this prospective, randomized, double-blind controlled study, infants with suspected non-IgE mediated CMA received test or control formula. Test formula was AAF with synbiotics (prebiotic fructo-oligosaccharides and probiotic Bifidobacterium breve M-16V). Control formula was AAF without synbiotics. Healthy, breastfed infants were used as a separate reference group (HBR). Bacterial compositions of faecal and salivary samples were analysed by 16S rRNA-gene sequencing. Faecal analysis was complemented with the analysis of pH, short-chain fatty acids (SCFAs) and lactic acids. RESULTS: The trial included 35 test subjects, 36 controls, and 51 HBR. The 16S rRNA-gene sequencing revealed moderate effects of test formula on oral microbiota. In contrast, the gut microbiota was substantially affected across time comparing test with control. In both groups bacterial diversity increased over time but was characterised by a more gradual increment in test compared to control. Compositionally this reflected an enhancement of Bifidobacterium spp. and Veillonella sp. in the test group. In contrast, the control-fed infants showed increased abundance of adult-like species, mainly within the Lachnospiraceae family, as well as within the Ruminococcus and Alistipes genus. The effects on Bifidobacterium spp. and Lachnospiraceae spp. were previously confirmed through enumeration by fluorescent in situ hybridization and were shown for test to approximate the proportions observed in the HBR. Additionally, microbial activity was affected as evidenced by an increase of l-lactate, a decrease of valerate, and reduced concentrations of branched-chain SCFAs in test versus control. CONCLUSIONS: The AAF including specific synbiotics effectively modulates the gut microbiota and its metabolic activity in non-IgE mediated CMA infants bringing it close to a healthy breastfed profile.Trial registration Registered on 1 May 2013 with Netherlands Trial Register Number NTR3979.

Oral exposure to the free amino acid glycine inhibits the acute allergic response in a model of cow's milk allergy in mice.

The conditionally essential amino acid glycine functions as inhibitory neurotransmitter in the mammalian central nervous system. Moreover, it has been shown to act as an anti-inflammatory compound in animal models of ischemic perfusion, post-operative inflammation, periodontal disease, arthritis and obesity. Glycine acts by binding to a glycine-gated chloride channel, which has been demonstrated on neurons and immune cells, including macrophages, polymorphonuclear neutrophils and lymphocytes. The present study aims to evaluate the effect of glycine on allergy development in a cow's milk allergy model. To this end, C3H/HeOuJ female mice were supplemented with glycine by oral gavage (50 or 100 mg/mouse) 4 hours prior to sensitization with cow's milk whey protein, using cholera toxin as adjuvant. Acute allergic skin responses and anaphylaxis were assessed after intradermal allergen challenge in the ears. Mouse mast cell protease-1 (mMCP-1) and whey specific IgE levels were detected in blood collected 30 minutes after an oral allergen challenge. Jejunum was dissected and evaluated for the presence of mMCP-1-positive cells by immunohistochemistry. Intake of glycine significantly inhibited allergy development in a concentration dependent manner as indicated by a reduction in; acute allergic skin response, anaphylaxis, serum mMCP-1 and serum levels of whey specific IgE. In addition, in-vitro experiments using rat basophilic leukemia cells (RBL), showed that free glycine inhibited cytokine release but not cellular degranulation. These findings support the hypothesis that the onset of cow's milk allergy is prevented by the oral intake of the amino acid glycine. An adequate intake of glycine might be important in the improvement of tolerance against whey allergy or protection against (whey-induced) allergy development.

Post-sensitization administration of non-digestible oligosaccharides and Bifidobacterium breve M-16V reduces allergic symptoms in mice.

To support dietary management of severe cow's milk allergic infants, a synbiotic mixture of non-digestible oligosaccharides and Bifidobacterium breve M-16V (B. breve) was designed from source materials that are completely cow's milk-free. It was investigated whether this specific synbiotic concept can reduce an established food allergic response in a research model for hen's egg allergy. Mice were orally sensitized once a week for 5 weeks to ovalbumin (OVA) using cholera toxin (CT) as an adjuvant. Non-sensitized mice received CT in PBS only. Sensitized mice were fed a control diet or a diet enriched with short-chain- (scFOS) and long-chain fructo-oligosaccharides (lcFOS), B. breve or scFOSlcFOS + B. breve for 3 weeks starting after the last sensitization. Non-sensitized mice received the control diet. Anaphylactic shock symptoms, acute allergic skin responses and serum specific IgE, mMCP-1 and galectin-9 were measured upon OVA challenge. Activated Th2-, Th1-cells and regulatory T-cells were quantified in spleen and mesenteric lymph nodes (MLN) and cytokine profiles were analyzed. Short chain fatty acids (SCFA) were measured in ceacal samples. The acute allergic skin response was reduced in mice fed the scFOSlcFOS + B. breve diet compared to mice fed any of the other diets. A reduction in mast cell degranulation (mMCP-1) and anaphylactic shock symptoms was also observed in these mice. Unstimulated splenocyte cultures produced increased levels of IL10 and IFNg in mice fed the scFOSlcFOS + B. breve diet. Correspondingly, increased percentages of activated Th1 cells were observed in the spleen. Allergen-specific re-stimulation of splenocytes showed a decrease in IL5 production. In summary; post-sensitization administration of scFOSlcFOS + B. breve was effective in reducing allergic symptoms after allergen challenge. These effects coincided with changes in regulatory and effector T-cell subsets and increases in the SCFA propionic acid. These results suggest immune modulatory benefits of dietary intervention with a unique combination of scFOSlcFOS + B. breve in established food allergy. Whether these effects translate to human applications is subject for ongoing clinical studies.

A potential role for regulatory T-cells in the amelioration of DSS induced colitis by dietary non-digestible polysaccharides.

Inflammatory bowel diseases (IBD) including ulcerative colitis (UC) and Crohn's disease (CD) are chronic relapsing inflammatory disorders of the gastrointestinal tract. The interaction between a disturbed microbial composition, the intestinal mucosal barrier and the mucosal immune system plays an important role in IBD and its chronicity. It has been indicated that due to the altered microbial composition the balance between T regulatory cells (Treg) and T helper cells (Th) 17 is disturbed, leading to an inflammatory state. The present study shows that oral intake of a specific multi fibre mix (MF), designed to match the fibre content of a healthy diet, counteracts IBD-like intestinal inflammation and weight loss in dextran sodium sulphate treated mice. This reduction in inflammation might be brought about, at least in part, by the MF-induced decrease in inflammatory cytokines, increase in IL-10 and the relative increase in Treg cells in the mesenteric lymph nodes (MLN). Moreover, the Treg percentage in the MLN correlates with the percentage of tolerogenic lamina propria derived CD103+RALDH+dendritic cells in the MLN, suggesting that these play a role in the observed effects. In children with CD exclusive enteral nutrition (EEN) is a widely used safe and effective therapy. Optimizing enteral nutritional concepts with the tested fibre mix, know to modulate the gut microbiota composition, SCFA production and inflammatory status (as indicated by the present study) could possibly further improve efficacy in inducing remission.

Cell biology of the adipokinetic hormone-producing neurosecretory cells in the locust corpus cardiacum.

The adipokinetic cells are neuron-like unipolar cells, the cell bodies and cell processes of which are intermingled within the glandular part of the corpus cardiacum. In Schistocerca gregaria, they produce two adipokinetic hormones, AKH-I and -II, whereas in Locusta migratoria an additional hormone, AKH-III, is present. The three AKHs are produced by the same cells and are co-localized in secretory granules. The biosynthesis and processing of the AKH prohormones to the bioactive hormones, which has been elucidated in detail for AKH-I and -II in S. gregaria, takes less than 75 min and goes on continuously. In older locusts in particular, the adipokinetic cells contain intracisternal granules, widely dilated cisternae of the rough endoplasmic reticulum, which function as stores of prohormones of AKH-I and -II, not of AKH-III. The adipokinetic cells are subjected to regulation by a number of neural and humoral substances, neural influences coming from secretomotor cells in the lateral part of the protocerebrum. Flight activity is the only natural stimulus unequivocally shown to induce the release of AKHs, which in L. migratoria results in parallel secretion of all three AKHs. During secretory stimulation, young secretory granules containing newly synthesized hormones are preferentially released over older granules. Secretory stimulation is not accompanied by a clear increase in the levels of the AKH mRNAs and the AKH prohormones and in the rate of synthesis of the (pro-)AKHs. Apparently, a coupling between release and biosynthesis of the AKHs in the adipokinetic cells is very loose or does not even exist.

Coherence between biosynthesis and secretion of insect adipokinetic hormones.

The importance of the process of continuous biosynthesis of locust adipokinetic hormones (AKHs) for the availability of these peptide hormones for release was assessed in vitro by inhibiting this biosynthesis followed by secretory stimulation. Inhibition of the biosynthetic activity for AKHs by brefeldin A caused a considerable inhibition of the AKH release induced by the endogenous crustacean cardioactive peptide (CCAP). After brefeldin A treatment followed by potassium depolarization, CCAP-induced AKH release was completely abolished. In vitro pulse-chase labeling experiments indicated that constitutive secretion from the AKH-producing cells does not occur. It is concluded that AKH secretion involves a regulated release from a relatively small pool of newly formed secretory granules, while older AKH-containing granules appear to be unavailable for release.