Discovery and characterization of taspoglutide, a novel analogue of human glucagon-like peptide-1, engineered for sustained therapeutic activity in type 2 diabetes.

AIM: Glucagon-like peptide-1 (GLP-1) receptor agonists for the treatment of type 2 diabetes are administered by daily injection because of short plasma half-lives, which result partly from the biochemical instability of these peptides. There is a medical need for GLP-1 analogues that can be administered less frequently for patient convenience. METHODS: We synthesized a series of human GLP-1 (hGLP-1(7-36)NH(2) ) derivatives containing α-aminoisobutyric acid (Aib) substitutions, analysed their enzymatic stabilities and evaluated their secondary structures using circular dichroism (CD) and nuclear magnetic resonance (NMR). RESULTS: Plasma stability experiments showed that only the analogue containing Aib substitutions in both the N-terminus (position 8) and the C-terminus (position 35), [Aib8(,)³5]hGLP-1(7-36)NH2 (BIM-51077), was fully resistant to enzymatic cleavage. Incubation with human plasma kallikrein or plasmin confirmed that the Aib substitution at position 35 prevented protease cleavage around this residue, which contributes to the significantly enhanced plasma stability and increased plasma half-life. CD revealed increased C-terminal α-helicity in Aib³5-substituted analogues compared with both hGLP-1(7-36)NH2 and analogues containing only Aib8 substitutions. Based on NMR studies, the secondary structure of BIM-51077 is similar to hGLP-1(7-36)NH2 with a slight increase in α-helicity in the C-terminus. Compared with hGLP-1(7-36)NH2, BIM-51077 had similar binding affinity for the human GLP-1 receptor and activated this receptor with similar potency. CONCLUSIONS: We have discovered an Aib8(,)³5-substituted analogue of native hGLP-1(7-36)NH2 (BIM-51077) that retains the structure of the native peptide, and has similar activity and enhanced stability. A sustained-release formulation of this molecule (taspoglutide) is in phase-3 clinical development.

Differences between pig tissues in the expression of major transplantation antigens: possible relevance for organ allografts.

Evidence is presented that there are differences between pig liver and kidney parenchymal cells in the expression of major histocompatibility complex antigens. Analogues of I-region antigens of the mouse are detectable on kidney cells and some peripheral blood leukocytes (PBL) but not on liver, platelets, and other PBL. Such differences between liver and kidney may explain (a) the fate of these organs as allografts and (b) the donor-specific protection of kidney by liver. Other antigens peculiar to skin and kidney have been detected but require further characterization.

A cusp singularity in surfaces that minimize an anisotropic surface energy.

A mathematical proof shows that a surface with a cusp-shaped singularity can arise from minimizing an anisotropic surface free energy for a portion of a crystal surface. Such cusps have been seen on crystal surfaces but usually have been interpreted as being the result of defects or nonequilibrium crystal growth. Our result predicts that they can occur as equilibrium or near-equilibrium phenomena. It also enriches the mathematical theory of minimal surfaces.

Multigroup invariance of the DAS across a random and an internet-sourced sample.

It is well established that angry and, subsequently, aggressive drivers pose a problem for road safety. Over recent years, there has been an increase in the number of published studies examining driver anger, particularly using the Driving Anger Scale (DAS). The DAS measures six broad types of situations likely to provoke anger while driving (i.e., police presence, illegal driving, discourtesy, traffic obstructions, slower drivers, and hostile gestures). The majority of the recent studies have moved away from traditional paper-and-pencil methodologies, using the internet to collect data, for reasons of convenience. However, it is not yet completely clear whether data obtained from this methodology differs from more traditional methods. While research outside of the driving arena has not found substantial differences, it is important to establish whether this also applies to driving-related research and measures, such as the DAS. The present study used Multigroup Confirmatory Factor Analysis (MGCFA) to investigate the invariance of the DAS across a random sample from the electoral roll (n = 1,081: males = 45%) and an internet sourced sample (n = 627; males = 55%). The MGCFA showed the same six-factor solution was supported in both datasets. The relationships between the DAS factors and age, sex, trait anger, and annual mileage were broadly similar, although more significant differences were identified in the internet sample. This research demonstrates that driving measures administered over the internet produce similar results to those obtained using more traditional methods.

Addressing prescription discrepancies in renal patients: a prospective audit.

Background Management of chronic renal failure requires complex medication regimens to manage hypertension, hyperlipidaemia, diabetes, phosphate, anaemia and acidosis. Patient engagement in medicine management is essential to avoid potential harm. Methods We prospectively audited the rate of discrepancies between our hospital record of patient medications and their current prescription. We investigated whether changes to appointment letters reduced the number of discrepancies. Results The proportion of patients attending renal outpatient clinics failing to bring a list or unable to recall their medications fell over a 3-year period following changes to appointment letters (median proportion: 0.45 in 2014, 0.36 in 2015, 0.30 in 2016, Chi-sq = 46.94, p < 0.001); percentage of patients forgetting to bring a list with significant prescription discrepancies fell from 10.9% in 2014 to 3.9% in 2016). Conclusion Changes to appointment letters can potentially improve prescribing safety in an outpatient setting.

The effect of ozone fumigation on the biogenic volatile organic compounds (BVOCs) emitted from Brassica napus above- and below-ground.

The emissions of BVOCs from oilseed rape (Brassica napus), both when the plant is exposed to clean air and when it is fumigated with ozone at environmentally-relevant mixing ratios (ca. 135 ppbv), were measured under controlled laboratory conditions. Emissions of BVOCs were recorded from combined leaf and root chambers using a recently developed Selective Reagent Ionisation-Time of Flight-Mass Spectrometer (SRI-ToF-MS) enabling BVOC detection with high time and mass resolution, together with the ability to identify certain molecular functionality. Emissions of BVOCs from below-ground were found to be dominated by sulfur compounds including methanethiol, dimethyl disulfide and dimethyl sulfide, and these emissions did not change following fumigation of the plant with ozone. Emissions from above-ground plant organs exposed to clean air were dominated by methanol, monoterpenes, 4-oxopentanal and methanethiol. Ozone fumigation of the plants caused a rapid decrease in monoterpene and sesquiterpene concentrations in the leaf chamber and increased concentrations of ca. 20 oxygenated species, almost doubling the total carbon lost by the plant leaves as volatiles. The drop in sesquiterpenes concentrations was attributed to ozonolysis occurring to a major extent on the leaf surface. The drop in monoterpene concentrations was attributed to gas phase reactions with OH radicals deriving from ozonolysis reactions. As plant-emitted terpenoids have been shown to play a role in plant-plant and plant-insect signalling, the rapid loss of these species in the air surrounding the plants during photochemical pollution episodes may have a significant impact on plant-plant and plant-insect communications.

Somatostatin receptor (SSTR) subtype-selective analogues differentially suppress in vitro growth hormone and prolactin in human pituitary adenomas. Novel potential therapy for functional pituitary tumors.

Previously, we have shown somatostatin receptor (SSTR) subtype-specific regulation of growth hormone (GH), thyroid-stimulating hormone, and prolactin (PRL) secretion in human fetal pituitary cultures, where GH and thyroid-stimulating hormone are mediated by both SSTR2 and SSTR5, whereas SSTR2 preferentially mediates PRL secretion. We now tested SSTR subtype-selective analogues in primary human GH- and PRL-secreting pituitary adenoma cultures. Analogue affinities determined by membrane radioligand binding in cells stably expressing human SSTR forms were either SSTR2 or SSTR5-selective. Analogues preferential either for SSTR2, including octreotide, lanreotide, and novel compounds with improved affinity for SSTR2, or new SSTR5-selective compounds suppressed GH in tumor cell cultures (up to 44% of control; P < 0.0005). However, novel analogues from both groups were 30-40% more potent than octreotide and lanreotide in suppressing GH (P < 0.05). Heterologous analogue combinations containing both SSTR2- and SSTR5-selective compounds were more potent in decreasing GH than analogues used alone (P < 0.05), or than combinations of compounds specific for the same receptor subtype (P < 0.005). In contrast, SSTR2-selective analogues did not suppress PRL release from six cultured prolactinomas studied. However, new SSTR5-selective analogues suppressed in vitro PRL secretion (30-40%; P < 0.05) in four of six prolactinomas. These results suggest that both SSTR2 and SSTR5 are involved in GH regulation in somatotroph adenoma cells, whereas SSTR5 exclusively regulates PRL secretion from prolactinoma cells. Thus, somatostatin analogues with improved selective binding affinity for these receptor subtypes may be effective in the treatment of either GH- or PRL-secreting adenomas.

Somatostatin receptor subtype specificity in human fetal pituitary cultures. Differential role of SSTR2 and SSTR5 for growth hormone, thyroid-stimulating hormone, and prolactin regulation.

Somatostatin (SRIF), a hypothalamic inhibitor of pituitary growth hormone (GH) and thyroid-stimulating hormone (TSH) secretion, binds to five distinct receptor (SSTR) subtypes. We therefore tested SSTR subtype-specific SRIF analogs in primary human fetal pituitary cultures (23-25-wk gestation) to elucidate their role in regulating human pituitary function. Using reverse transcription-PCR, mRNA expression of SSTR2 and SSTR5 were detected in fetal pituitary by 25 wk. SRIF analog affinities were determined by membrane radioligand binding in cells stably expressing the human SSTR forms. GH secretion was suppressed equally (40-60%, P < 0.005) by analogs preferential for either SSTR2 (IC50 for receptor binding affinity, 0.19-0.42 nM) or SSTR5 (IC50, 0.37 nM), and compounds with enhanced affinity for SSTR2 were more potent (EC50 for GH suppression, 0.05-0.09 nM) than Lanreotide (EC50, 2.30 nM) and SRIF (EC50, 0.19 nM). Similarly, analogs with high affinity for SSTR2 or SSTR5 decreased TSH secretion (30-40%, P < 0.005). However, prolactin was effectively inhibited only by compounds preferentially bound to SSTR2 (20-30%, P < 0.05). Luteinizing hormone was modestly decreased (15-20%) by SSTR2- or SSTR5-specific analogs. An SSTR5-specific analog also exclusively inhibited GH in acromegalic tumor cells. Thus, SRIF regulation of GH and TSH in primary human fetal pituitary cells is mediated by both SSTR2 and SSTR5, both of which are abundantly expressed by 25 wk. In contrast, suppression of prolactin is mediated mainly by SSTR2. These results indicate that SSTR5 is critical for physiologic regulation of GH and TSH. SRIF analogs with selective affinity for this receptor may therefore be more effective in the treatment of hormone-secreting pituitary adenomas.

Stimulus-Induced Oscillations in Guard Cell Cytosolic Free Calcium.

Ca2+ is implicated as a second messenger in the response of stomata to a range of stimuli. However, the mechanism by which stimulus-induced increases in guard cell cytosolic free Ca2+ ([Ca2+]i) are transduced into different physiological responses remains to be explained. Oscillations in [Ca2+]i may provide one way in which this can occur. We used photometric and imaging techniques to examine this hypothesis in guard cells of Commelina communis. External Ca2+ ([Ca2+]e), which causes an increase in [Ca2+]i, was used as a closing stimulus. The total increase in [Ca2+]i was directly related to the concentration of [Ca2+]e, both of which correlated closely with the degree of stomatal closure. Increases were oscillatory in nature, with the pattern of the oscillations dependent on the concentration of [Ca2+]e. At 0.1 mM, [Ca2+]e induced symmetrical oscillations. In contrast, 1.0 mM [Ca2+]e induced asymmetric oscillations. Oscillations were stimulus dependent and modulated by changing [Ca2+]e. Experiments using Ca2+ channel blockers and Mn2+-quenching studies suggested a role for Ca2+ influx during the oscillatory behavior without excluding the possible involvement of Ca2+ release from intracellular stores. These data suggest a mechanism for encoding the information required to distinguish between a number of different Ca2+-mobilizing stimuli in guard cells, using stimulus-specific patterns of oscillations in [Ca2+]i.

Regulation of insulin and glucagon secretion from rat pancreatic islets in vitro by somatostatin analogues.

Somatostatin is an inhibitor of hormone secretion through specific receptors (sst1-5). The aim of this study was to investigate the putative regulatory role of somatostatin analogues on the secretion of insulin and glucagon by rat pancreatic islets. After 48 h exposure only the non-selective agonists (somatostatin, octreotide and SOM-230) inhibited insulin accumulation. The inhibition of insulin secretion was accompanied by increased islet insulin contents. None of the analogues showed a consistent effect on the glucagon accumulation in the medium after 48 h. Since we observed a difference in the regulatory effect between the non-selective and selective analogues, combinations of selective analogues were studied. Combination of sst2+sst5 agonists inhibited the medium insulin accumulation, while combination of sst1+sst2 analogues caused a decrease in glucagon accumulation. After removal of somatostatin a rebound effect with increased insulin secretion were observed. This effect was reversed after 6 h. For SOM-230 insulin secretion continued to be suppressed even after the analogue was removed and returned to control values after 3 h. As for glucagon secretion there was an initial decline after culture with octreotide, while the other substances failed to induce any changes. In summary, non-selective somatostatin analogues or combinations of receptor selective analogues may cause inhibition of hormone secretion from rat pancreatic islets. For insulin and glucagon, combinations of sst2+sst5 and sst1+sst2, respectively may exert this effects. Thus, our data suggest that more than one sst must be involved to down-regulate islet glucagon and insulin secretion.

Does metabolic syndrome mitigate weight loss in overweight Mexican American women treated for 1-year with orlistat and lifestyle modification?

AIMS: To investigate the effects of a pharmacotherapy (orlistat) plus lifestyle management (OLM) intervention on weight loss in Mexican American women with and without metabolic syndrome (MS). METHODS: One hundred and seven female participants aged 21-65 years and of Mexican origin were randomized to either OLM or a wait-list control group (WLC) for one year. The lifestyle interventions were tailored to exhibit features of the Mexican culture. Within each group, subjects with MS were compared to those without MS to assess whether its presence mitigates weight loss. Risk factors for MS also were assessed. RESULTS: Participants with MS in the OLM group experienced significant decreases in weight and body mass index (BMI) as compared to participants without MS. Participants with MS in the OLM group and who completed the study lost 9.3+/-7.5 kg (20.5+/-16.5 lb) as compared to participants with MS in the WLC group, who only lost 0.2+/-3.1 kg (0.4+/-6.8 lb). Further, participants with MS in the OLM group who completed the study experienced a 3.1+/-3.9 kg/m2 decrease in BMI whereas participants with MS in the WLC group only experienced a 0.1+/-1.2 kg/m2 decrease in BMI. No changes in other MS risk factors were significant. CONCLUSIONS: Patients with MS experienced significant weight loss and decreases in BMI as a result of a lifestyle and pharmacotherapy intervention.

Coping with multiple enemies: an integration of molecular and ecological perspectives.

How plants respond to attack by the range of herbivores and pathogens that confront them in the field is the subject of considerable research by both molecular biologists and ecologists. However, in spite of the shared focus of these two bodies of research, there has been little integration between them. We consider the scope for such integration, and how greater dialogue between molecular biologists and ecologists could advance understanding of plant responses to multiple enemies.

Treatment of R-3327 prostate tumors with a somatostatin analogue (somatuline) as adjuvant therapy following surgical castration.

This study addresses, in an animal tumor model, the clinical problem of "escape from castration inhibition." Somatuline (BIM-23014C), an octapeptide analogue of somatostatin with enhanced potency and longer duration of biological activity was administered as a therapeutic agent, over a period of 90 and 197 days, to male Copenhagen rats bearing syngeneic Dunning R-3327-H prostate tumors. Androgen sensitivity was confirmed by the response of tumors to castration and by the significant inhibition of tumor growth in intact animals by treatment with a luteinizing hormone-releasing hormone antagonist (BIM-21009). Inhibition of tumor growth resulting from castration persisted for 102 days, after which progressive regrowth occurred, indicating an escape from castration inhibition. When Somatuline treatment was initiated as an adjuvant therapy 5 days after castration, the rate of tumor regrowth during escape was significantly retarded. During the period of 197 days postcastration, tumors in the vehicle-treated, intact controls grew to an average diameter of 38.6 +/- 7.6 mm and tumors in vehicle-treated castrate controls grew to an average diameter of 23.3 +/- 4.1 mm (60% test/control). Treatment with the luteinizing hormone-releasing hormone antagonist induced no significant additional tumor inhibitory effects in castrated animals which developed tumors having an average diameter of 30.2 +/- 8.2 mm (78% test/control). Treatment of tumors in castrate animals with Somatuline, on the other hand, induced a significant (P less than 0.01) tumor-inhibitory effect that was greater than that produced by castration alone, developing an average tumor diameter of only 14.3 +/- 2.6 mm, (37% test/control). A growth inhibitory effect was also inducible in animals having tumors that had already escaped castration inhibition. The relative nontoxicity of a somatostatin analogue such as Somatuline suggests that chronic or maintenance therapy of slow-growing prostate cancers may be both feasible and acceptable in a clinical setting.

Response of human lung tumor xenografts to treatment with a somatostatin analogue (Somatuline).

Four human small cell lung carcinomas, NCI-H69, NCI-N417, NCI-H345, LX-1, and a non-small cell lung carcinoma, H-165, implanted s.c. as tumor xenografts in athymic nude mice, were treated with Somatuline (BIM-23014C), an endocrinologically potent octapeptide analogue of somatostatin. All tumors responded, although in varying degrees, with percentage of test/control values ranging from 3 to 88. Somatuline administered as a perilesional infusion effectively inhibited xenograft growth inducing prolonged remissions. When treatment was terminated, some tumors regrew, suggesting antimitogenic activity rather than cytocidal. Absence of observable systemic or local toxicity during prolonged treatment would support this conclusion and suggest the feasibility of long term maintenance therapy with a resultant extended survival.

Classification and nomenclature of somatostatin receptors.

There is considerable controversy about the classification and nomenclature of somatostatin receptors. To date, five distinct receptor genes have been cloned and named chronologically according to their respective publication dates, but two were unfortunately given the same appellation (SSTR4). Consensually, a nomenclature for the recombinant receptors has been agreed according to IUPHAR guidelines (sst1, sst2, sst3, sst4, and sst5). However, a more informative classification is to be preferred for the future, employing all classification criteria in an integrated scheme. It is already apparent that the five recombinant receptors fall into two classes or groups, on the basis of not only structure but also pharmacological characteristics. One class (already referred to by some as SRIF1) appears to comprise sst2, sst3 and sst5 receptor subtypes. The other class (SRIF2) appears to comprise the other two recombinant receptor subtypes (sst1 and sst4). This promising approach is discussed but it is acknowledged that much more data from endogenous receptors in whole tissues are needed before further recommendations on somatostatin receptor nomenclature can be made.

Joint attention for stimuli on the hands: ownership matters.

The visual system treats the space near the hands with unique, action-related priorities. For example, attention orients slowly to stimuli on the hands (Taylor and Witt, 2014). In this article, we asked whether jointly attended hands are attended in the same way. Specifically, we examined whether ownership over the hand mattered: do we attend to our hands and the hands of others in the same way? Pairs of participants performed a spatial cueing task with stimuli that could be projected onto one partner's hands or on a control surface. Results show delayed orienting of attention to targets appearing on the hands, but only for the owner of the hands. For an observer, others' hands are like any other surface. This result emphasizes the importance of ownership for hand-based effects on vision, and in doing so, is inconsistent with some expectations of the joint action literature.

In vivo and in vitro stimulation of growth hormone release in chickens by synthetic human pancreatic growth hormone releasing factor (hpGRFs).

The effect of the synthetic human pancreatic GH releasing factors (hpGRFs, hpGRF44 and hpGRF40) on GH release was studied both in vivo and in vitro. Four-week-old cockerels were injected iv with hpGRFs at 0.1 microgram, 1.0 microgram, and 10.0 micrograms/bird. The 0.1 microgram dose of hpGRFs had no effect on plasma GH levels, but the 1.0 microgram and 10.0 micrograms doses of hpGRFs caused a dose-dependent elevation of plasma GH. Plasma GH levels returned to basal 60 min after injection. HpGRFs, thyrotropin releasing hormone (TRH) and somatostatin (SRIF) were examined in a chicken in vitro pituitary cell culture system. In vitro hpGRFs and TRH caused a significant dose-dependent release of chicken GH, and the ability to stimulate GH was additive when hpGRF44 and TRH were added together in the culture medium. SRIF showed no consistent effect on the release of chicken GH, but it inhibited the stimulatory effect of hpGRF44 on chicken GH release. We conclude that hpGRF is a potent releaser of chicken GH in vivo and in vitro.

Purified chicken growth hormone (GH) and a human pancreatic GH-releasing hormone increase body weight gain in chickens.

Purified chicken GH (cGH) and a synthetic human GH-releasing hormone (hpGRF) were tested for the ability to improve growth performance in chickens. Purified cGH was given to 4-week-old cockerels at 5, 10, and 50 micrograms/day for 14 days via daily iv injection. Body weights of chickens receiving 5 and 10 micrograms/day cGH were significantly increased at 6 days by 13.5% and 11.2%, respectively, relative to control values. At 14 days, body weights averaged 8.1% and 7.7% greater than controls, but these values were not statistically significant. There was a slight stimulation of body weight gain in chickens receiving 50 micrograms/day cGH. In general, cGH produces a transient stimulation of body weight gain in chickens. hpGRF was also given to 4-week-old cockerels for 14 days via daily iv injection at 0.1, 1.0, and 10.0 micrograms/day. hpGRF at 0.1 microgram/bird daily increased body weight on day 14 (9.1% over the control value). The stimulating effects of hpGRF on body weight are also transient. The effects of cGH on serum somatomedin-C (SM-C) were examined. Serum SM-C concentrations were significantly elevated 24 and 36 h after injection of cGH. In conclusion, purified cGH and hpGRF appear to have some growth-promoting activity. The stimulatory effect of hpGRF on weight gain may be mediated via GH, and the stimulatory effect of cGH could be mediated through SM-C.

Thyrotropin-releasing hormone stimulates body weight gain and increases thyroid hormones and growth hormone in plasma of cockerels.

The effect of TRH on growth in 4-week-old cockerels was examined in two separate experiments. Daily injection of TRH via the brachial vein stimulated growth in 4-week-old cockerels over 17 days of treatment in the first experiment and over 25 days in the second. In the first experiment, TRH at 1.0 micrograms and 10.0 micrograms/bird caused significant (P less than 0.05) increases of 12.0% and 12.4%, respectively, in growth rate, whereas in the second experiment, only the 1.0 micrograms/bird level of TRH caused an increase (P less than 0.05). In each experiment, the increase in body weight gain was not TRH dose dependent, and neither feed consumption nor feed efficiency was affected. Possible involvement of pituitary hormones in TRH-stimulated growth in cockerels was studied in a separate experiment, and the effects of TRH on plasma T3, T4, and GH were examined. TRH was given iv at 0.1, 1.0, and 10.0 micrograms/bird daily for 5 days, and plasma T3, T4, and GH concentrations were measured 15, 60, and 180 min postinjection by RIA on days 1, 3, and 5. The responses of T3 and T4 to TRH were greatest on day 1, were diminished by days 3 and 5, and were not dose-related. Significant, not dose-related, elevations of plasma GH concentrations were obtained at all doses of TRH. Based on these results, we suggest that TRH has the ability to promote a significant increase in body weight gain in 4-week-old cockerels, and the stimulatory effects may be mediated through GH and/or thyroid hormones.

Characterization of new selective somatostatin receptor subtype-2 (sst2) antagonists, BIM-23627 and BIM-23454. Effects of BIM-23627 on GH release in anesthetized male rats after short-term high-dose dexamethasone treatment.

We here report a pharmacological characterization of two new somatostatin (SS) receptor subtype-2 (sst2) selective antagonists by evaluating their GH-releasing activity when administered, by different routes, in anesthetized adult rats and in freely moving 10-d-old rats. Moreover, we describe the effect of these SS antagonists on the GH response to GHRH after short-term high-dose dexamethasone (DEX) treatment in young male rats. BIM-23454 and BIM-23627, given iv, were able to counteract the SS-induced inhibition of GH secretion occurring after urethane anesthesia in a dose-dependent manner. In DEX-treated animals, the GH response to GHRH was partially blunted (5-min peak values, 270 +/- 50 ng/ml in saline-treated vs. 160 +/- 10 ng/ml in DEX-treated, P < 0.05); however, the simultaneous administration of BIM-23627 (0.2 mg/kg, iv) restored higher amplitude GH pulse, leading to a significantly higher overall mean GH response (area under the curve, 4200 +/- 120 ng/ml/30 min vs. 2800 +/- 100 ng/ml/30 min after GHRH alone; P < 0.05). The SS antagonists showed a reduced GH-releasing effect when administered sc or ip, likely attributable to decreased bioavailability, as compared with the iv route. SS antagonist administration also increased plasma glucagon, insulin, and glucose levels. Based on prior reports that sst2 tonically suppresses glucagon secretion, the antagonist most likely increased glucagon secretion from the pancreatic alpha-cells, with resultant increases in plasma glucose and then insulin.