Qualification of In Vitro Dissolution Absorption System 2 (IDAS2) with Caco-2 and MDCK Cell Monolayers: Dose Sensitivity Study Using BCS Class I and III Drugs.

This study aimed to validate the In vitro Dissolution Absorption System 2 (IDAS2) containing a biological barrier of Caco-2 or Madin-Darby canine kidney (MDCK) cell monolayer through dose sensitivity studies. Metoprolol and propranolol were selected as Biopharmaceutics Classification System (BCS) Class I model drugs, and atenolol as a Class III model drug. The IDAS2 is comprised of a dissolution vessel (500 mL) and two permeation chambers (2 × 8.0 mL) mounted with Caco-2 or MDCK cell monolayer. One or two immediate-release tablet(s) of the model drug were added to the dissolution vessel, and the time profiles of dissolution and permeation were observed. Greater than 85% of metoprolol and propranolol (tested at two dosing concentrations) were dissolved by 15 min, and all drugs were fully dissolved by 30 min. All three drugs were more permeable across Caco-2 cells than MDCK cells with a linear increase in permeation across both cells at both dose concentrations. Thus, the dose sensitivity of the IDAS2 was demonstrated using both cell barriers. These results indicate a successful qualification of IDAS2 for the development/optimization of oral formulations and that MDCK cells can be utilized as a surrogate for Caco-2 cells.

Ocular pharmacokinetics of atenolol, timolol and betaxolol cocktail: Tissue exposures in the rabbit eye.

Quantitative understanding of pharmacokinetics of topically applied ocular drugs requires more research to further understanding and to eventually allow predictive in silico models to be developed. To this end, a topical cocktail of betaxolol, timolol and atenolol was instilled on albino rabbit eyes. Tear fluid, corneal epithelium, corneal stroma with endothelium, bulbar conjunctiva, anterior sclera, iris-ciliary body, lens and vitreous samples were collected and analysed using LC-MS/MS. Iris-ciliary body was also analysed after intracameral cocktail injection. Non-compartmental analysis was utilized to estimate the pharmacokinetics parameters. The most lipophilic drug, betaxolol, presented the highest exposure in all tissues except for tear fluid after topical administration, followed by timolol and atenolol. For all drugs, iris-ciliary body concentrations were higher than that of the aqueous humor. After topical instillation the most hydrophilic drug, atenolol, had 3.7 times higher AUCiris-ciliary body than AUCaqueous humor, whereas the difference was 1.4 and 1.6 times for timolol and betaxolol, respectively. This suggests that the non-corneal route (conjunctival-scleral) was dominating the absorption of atenolol, while the corneal route was more important for timolol and betaxolol. The presented data increase understanding of ocular pharmacokinetics of a cocktail of drugs and provide data that can be used for quantitative modeling and simulation.

Efficacy and Safety of Propranolol vs Atenolol in Infants With Problematic Infantile Hemangiomas: A Randomized Clinical Trial.

Importance: Propranolol has become the first-line therapy for problematic infantile hemangiomas (IHs) that require systemic therapy. However, different adverse events have been reported during propranolol treatment. The positive efficacy and safety of atenolol raise the question of whether it could be used as a promising therapy for IH. Objective: To compare the efficacy and safety of propranolol vs atenolol in infants (between age 5 and 20 weeks) with problematic IHs who required systemic therapy. Design, Setting, and Participants: This was a prospective, multicenter, randomized, controlled, open-label clinical trial conducted in collaboration among 6 separate investigation sites in China from February 1, 2015, to December 31, 2018. A total of 377 patients met the criteria for inclusion and were randomized to the propranolol (190 [50.4%]) and atenolol (187 [49.6%]) groups. Data were analyzed in June 2020. Interventions: Participants were randomized to receive either propranolol or atenolol for at least 6 months. They completed efficacy assessments at 2 years after the initial treatment. Main Outcomes and Measures: The primary outcome was any response or nonresponse at 6 months. The key secondary outcome was changes in the hemangioma activity score. Results: Of 377 participants, 287 (76.1%) were female, and the mean (SD) age was 10.2 (4.0) weeks in the propranolol group and 9.8 (4.1) weeks in the atenolol group. After 6 months of treatment, in the propranolol and atenolol groups, the overall response rates were 93.7% and 92.5%, respectively (difference, 1.2%; 95% CI, -4.1% to 6.6%). At 1 and 4 weeks after treatment, and thereafter, the hemangioma activity score in the atenolol group aligned with the propranolol group (odds ratio, 1.034; 95% CI, 0.886-1.206). No differences between the propranolol group and atenolol group were observed in successful initial responses, quality of life scores, complete ulceration healing times, or the rebound rate. Both groups presented a similar percentage of complete/nearly complete responses at 2 years (82.1% vs 79.7%; difference, 2.4%; 95% CI, -5.9% to 10.7%). Adverse events were more common in the propranolol group (70.0% vs 44.4%; difference, 25.6%; 95% CI, 15.7%-34.8%), but the frequency of severe adverse events did not differ meaningfully between the groups. Conclusions and Relevance: In this randomized clinical trial, when compared with propranolol, atenolol had similar efficacy and fewer adverse events in the treatment of infants with problematic IHs. The results suggest that oral atenolol can be used as an alternative treatment option for patients with IH who require systemic therapy. Trial Registration: ClinicalTrial.gov Identifier: NCT02342275.

Do beta-adrenergic blocking agents increase asthma exacerbation? A network meta-analysis of randomized controlled trials.

Beta-adrenergic blocking agents (abbreviated as beta-blockers) have been used for treating various cardiovascular diseases. However, the potential for asthma exacerbation is one of the major adverse effects of beta-blockers. This study aimed to compare the level of risk for an asthma attack in patients receiving various beta-blockers. We searched for randomized controlled trials (RCTs) of either placebo-controlled or active-controlled design. The current network meta-analysis (NMA) was conducted under a frequentist model. The primary outcome was the incidence of asthmatic attack. A total of 24 RCTs were included. Overall NMA revealed that only oral timolol [risk ratio (RR) = 3.35 (95% confidence interval (CI) 1.04-10.85)] and infusion of propranolol [RR = 10.19 (95% CI 1.29-80.41)] were associated with significantly higher incidences of asthma attack than the placebo, whereas oral celiprolol [RR = 0.39 (95% CI 0.04-4.11)], oral celiprolol and propranolol [RR = 0.46 (95% CI 0.02-11.65)], oral bisoprolol [RR = 0.46 (95% CI 0.02-11.65)], oral atenolol [RR = 0.51 (95% CI 0.20-1.28)], infusion of practolol [RR = 0.80 (95% CI 0.03-25.14)], and infusion of sotalol [RR = 0.91 (95% CI 0.08-10.65)] were associated with relatively lower incidences of asthma attack than the placebo. In participants with a baseline asthma history, in addition to oral timolol and infusion of propranolol, oral labetalol, oxprenolol, propranolol, and metoprolol exhibited significantly higher incidences of asthma attack than did the placebo. In conclusion, oral timolol and infusion of propranolol were associated with a significantly higher risk of developing an asthma attack in patients, especially in those with a baseline asthma history, and should be avoided in patients who present a risk of asthma.Trial registration: PROSPERO CRD42020190540.

Polypill with or without Aspirin in Persons without Cardiovascular Disease.

BACKGROUND: A polypill comprising statins, multiple blood-pressure-lowering drugs, and aspirin has been proposed to reduce the risk of cardiovascular disease. METHODS: Using a 2-by-2-by-2 factorial design, we randomly assigned participants without cardiovascular disease who had an elevated INTERHEART Risk Score to receive a polypill (containing 40 mg of simvastatin, 100 mg of atenolol, 25 mg of hydrochlorothiazide, and 10 mg of ramipril) or placebo daily, aspirin (75 mg) or placebo daily, and vitamin D or placebo monthly. We report here the outcomes for the polypill alone as compared with matching placebo, for aspirin alone as compared with matching placebo, and for the polypill plus aspirin as compared with double placebo. For the polypill-alone and polypill-plus-aspirin comparisons, the primary outcome was death from cardiovascular causes, myocardial infarction, stroke, resuscitated cardiac arrest, heart failure, or revascularization. For the aspirin comparison, the primary outcome was death from cardiovascular causes, myocardial infarction, or stroke. Safety was also assessed. RESULTS: A total of 5713 participants underwent randomization, and the mean follow-up was 4.6 years. The low-density lipoprotein cholesterol level was lower by approximately 19 mg per deciliter and systolic blood pressure was lower by approximately 5.8 mm Hg with the polypill and with combination therapy than with placebo. The primary outcome for the polypill comparison occurred in 126 participants (4.4%) in the polypill group and in 157 (5.5%) in the placebo group (hazard ratio, 0.79; 95% confidence interval [CI], 0.63 to 1.00). The primary outcome for the aspirin comparison occurred in 116 participants (4.1%) in the aspirin group and in 134 (4.7%) in the placebo group (hazard ratio, 0.86; 95% CI, 0.67 to 1.10). The primary outcome for the polypill-plus-aspirin comparison occurred in 59 participants (4.1%) in the combined-treatment group and in 83 (5.8%) in the double-placebo group (hazard ratio, 0.69; 95% CI, 0.50 to 0.97). The incidence of hypotension or dizziness was higher in groups that received the polypill than in their respective placebo groups. CONCLUSIONS: Combined treatment with a polypill plus aspirin led to a lower incidence of cardiovascular events than did placebo among participants without cardiovascular disease who were at intermediate cardiovascular risk. (Funded by the Wellcome Trust and others; TIPS-3 ClinicalTrials.gov number, NCT01646437.).

Poly(Acrylic Acid)-Modified MoS2 Nanoparticle-Based Transdermal Delivery of Atenolol.

INTRODUCTION: Hypertension is a major health problem worldwide and is typically treated using oral drugs. However, the frequency of oral administration may result in poor patient compliance, and reduced bioavailability owing to the first-pass effect can also prove problematic. METHODS: In this study, we developed a new transdermal-drug-delivery system (TDDS) for the treatment of hypertension using atenolol (ATE) based on poly(acrylic acid) (PAA)-decorated three-dimensional (3D) flower-like MoS2 nanoparticles (PAA-MoS2 NPs) that respond to NIR laser irradiation. The PAA-modified MoS2 NPs were synthesized and characterized using attenuated total reflection Fourier-transform infrared spectroscopy, X-ray diffraction measurements, scanning electron microscopy, transmission electron microscopy, dynamic light scattering, and the sedimentation equilibrium method. The drug-loading efficiency and photothermal conversion effect were also explored. RESULTS: The results showed that the colloidally stable PAA-MoS2 NPs exhibited a high drug-loading capacity of 54.99% and high photothermal conversion ability. Further, the capacity of the PAA-MoS2 NPs for controlled release was explored using in vitro drug-release and skin-penetration studies. The drug-release percentage was 44.72 ± 1.04%, and skin penetration was enhanced by a factor of 1.85 in the laser-stimulated group. Sustained and controlled release by the developed TDDS were observed with laser stimulation. Moreover, in vivo erythema index analysis verified that the PAA-MoS2 NPs did not cause skin irritation. DISCUSSION: Our findings demonstrate that PAA-MoS2 NPs can be used as a new carrier for transdermal drug delivery for the first time.

Atenolol in cats with subclinical hypertrophic cardiomyopathy: a double-blind, placebo-controlled, randomized clinical trial of effect on quality of life, activity, and cardiac biomarkers.

OBJECTIVE: To compare quality of life (QOL) and activity measures between healthy control cats and cats with subclinical hypertrophic cardiomyopathy (HCM), and to evaluate the effect of oral atenolol therapy on QOL, activity, and circulating biomarkers in cats with subclinical HCM. ANIMALS: Thirty-two client-owned cats with subclinical HCM and 27 healthy control cats. METHODS: Owner responses to a QOL questionnaire, circulating cardiac biomarker concentrations, and accelerometer-based activity measures were compared prospectively in cats with and without HCM, and in cats with HCM before and after treatment with oral atenolol (6.25 mg/cat q 12 h) for 6 months. RESULTS: Owner-assessed activity of daily living score was lower in cats with HCM than in cats in controls (p=0.0420). No differences were identified between control cats and cats with HCM for any activity variable. Compared with placebo, treatment with atenolol was associated with a lower baseline-adjusted mean ± SD heart rate (157 ± 30 vs. 195 ± 20 bpm; p=0.0001) and rate-pressure product (22,446 ± 6,237 vs. 26,615 ± 4,623 mmHg/min; p=0.0146). A treatment effect of atenolol on QOL or activity was not demonstrated. CONCLUSIONS: This study failed to identify an effect of subclinical HCM on owner-assessed QOL or activity or a treatment effect of atenolol on these variables at the dosage evaluated. These findings do not support a treatment benefit of atenolol for the goal of symptom reduction in cats with subclinical HCM.

Functionalized MoS2-nanoparticles for transdermal drug delivery of atenolol.

Molybdenum disulfide (MoS2) has excellent photothermal conversion abilities, an ultra-high specific surface area, and has been extensively explored for use in biomedicine. However, the high toxicity associated with MoS2 has limited its biological applications for in vivo photothermal therapy and drug delivery systems. Herein, we have developed cationic hydroxyethyl cellulose (JR400) surface-modified MoS2 nanoparticles (NPs) that are responsive to near-infrared (NIR) laser irradiation as a transdermal drug delivery system (TDDS). Herein, we confirmed the preparation of hexagonal phase MoS2 with robust surface modification with JR400. The flower-like morphology of the NPs had an average diameter of 355 ± 69.3 nm limiting the absorption of the NPs through the stratum corneum. With the ability to efficiently load 90.4 ± 0.3% of the model drug atenolol (ATE), where 1 g of JR400-MoS2 NPs was able to load 3.6 g ATE, we assayed the controlled release capacity in vitro skin penetration studies. These JR400-MoS2 NPs showed further enhancement under NIR stimulation, with a 2.3-fold increase in ATE skin penetration. Furthermore, we verified in vivo that these JR400-MoS2 NPs do not cause skin irritation suggesting that they are promising new TDDS candidates for small molecule drugs.

Effects of atenolol injected into the nucleus accumbens septi in rats in the elevated plus-maze test.

Background In previous studies, we have observed that glutamate antagonists injected within the nucleus accumbens septi (NAS) induced an anxiolytic-like effect in the elevated plus maze (EPM) test in rats. In the present study, the effect of Atenolol, a specific Beta Adreno-receptor antagonist in the EPM was studied in male rats bilaterally cannulated NAS. Methods Rats were divided into five groups that received either 1 µL injections of saline or atenolol in different doses (0.75, 1 or 2 µg/1 µL, n=15-16) 15 min before testing. Results Time Spent in the Open Arm was modified by treatment (F=4.563, p=0.006, df 3). This was increased by the lowest dose of atenolol (p<0.05), by the medium doses (p<0.001) and also by the highest dose (p<0.01). Time per Entry was modified by treatment (F=4.54, p=0.06, df 3). This parameter was increased by the lowest dose of atenolol (p<0.01), but not for the medium and higher doses. Conclusions We conclude that Atenolol beta receptor blockade in the accumbens lead to an anxiolytic-like effect related to an increase in the time spent in the open arm and in the time per entry, showing specific behavioral patterns.

Effect of Common Excipients on Intestinal Drug Absorption in Wistar Rats.

The aim of the present paper is to study the effect of common excipients on the permeability of atenolol (as drug absorbed mainly by passive diffusion) and rhodamine (as P-glycoprotein substrate). The apparent permeability was measured by an in situ perfusion method in Wistar rats using the closed loop Doluisio's method. Permeability values were characterized in the absence and presence of 18 commonly used excipients. Excipient concentrations were selected based on the amounts in oral immediate release dosage forms, which failed the test during the human bioequivalence studies. Atenolol was studied with and without excipients in the whole small intestine, whereas rhodamine was tested in three different intestinal segments to account for the differential expression of P-glycoprotein, and it was further on tested in the ileum, in the presence of excipients. Atenolol presented higher permeability values when it was administered with colloidal silica, croscarmellose, hydroxypropyl methylcellulose (HPMC), magnesium stearate, MgCO3, poly(ethylene glycol) 400, poly(vinylpyrrolidone), sorbitol, starch, and TiO2 rhodamine showed higher permeability values when it was administered with croscarmellose and HPMC. On the one hand, the mechanisms of action were not discernible with the proposed experiments. On the other hand, commercial formulations do not present a single excipient but several, which can counteract their effects. The in situ perfusion technique can be useful for a preliminary screening and risk analysis, while the in vivo pharmacokinetic results would be needed to define conclusive effects.

Multicap to improve adherence after acute coronary syndromes: results of a randomized controlled clinical trial.

BACKGROUND: Adherence to treatment after a myocardial infarction (MI) is poor, even in the early postinfarction period. Combining evidence-based drugs into a multicap could improve adherence in this population. No previous randomized trial assessing fixed-dose combination therapy has included patients early after a MI. We aimed to assess if a multicap containing four secondary prevention drugs increases adherence to treatment at 6 months after MI hospitalization. The study was designed as a randomized, parallel, open-label, controlled trial. METHODS: Patients were randomized within 7 days of a MI to either multicap or control group. The multicap group received a capsule containing aspirin, atenolol, ramipril, and simvastatin. The control group received each drug in separate pills. The primary outcome was adherence at 6 months. We also measured blood pressure, heart rate, serum cholesterol levels, C-reactive protein, and platelet aggregation. RESULTS: The study was stopped prematurely when 100 patients were included for futility. At 6 months, 92 (95.8%) patients were adherent to medical treatment: 98.0% in the multicap group and 93.5% in the control group [relative risk (RR) 1.05; 95% confidence interval (CI) 0.96-1.14; p = 0.347]. There were no differences between groups in systolic blood pressure (p = 0.662), diastolic blood pressure (p = 0.784), heart rate (p = 0.533), total cholesterol (p = 0.760), LDL-c (p = 0.979), C-reactive protein (p = 0.399), or in the proportion of patients with adequate platelet aggregation inhibition (p = 0.600). CONCLUSIONS: The study did not find any improvement in the adherence at 6 months after a MI with a multicap-based strategy (Multicap for Increase Adherence After Acute Myocardial Infarction; [ ClinicalTrials.gov identifier: NCT02271178]).

Atenolol oral en el manejo del hemangioma infantil: serie de casos de 46 pacientes / Oral Atenolol for Infantile Hemangioma: Case Series of 46 Infants

El propranolol, un betabloqueante no selectivo, sigue siendo la primera línea de tratamiento para el hemangioma infantil problemático. Sin embargo, aunque poco frecuente, un subgrupo de pacientes experimenta efectos secundarios indeseables, lo que despierta el interés sobre otros betabloqueantes selectivos. Presentamos una amplia serie de casos de 46 lactantes tratados con éxito con atenolol, un bloqueante selectivo beta-1

Propranolol, a non-selective beta-blocker, remains the first line of treatment for problematic infantile hemangioma. However, although rarely, a subset of patients experience undesirable side effects, raising interest in other selective beta-blockers. We present a large case series of 46 infants treated successfully with oral atenolol, a selective beta-1 blocker

Oral Atenolol for Infantile Hemangioma: Case Series of 46 Infants. / Atenolol oral en el manejo del hemangioma infantil: serie de casos de 46 pacientes.

Propranolol, a non-selective beta-blocker, remains the first line of treatment for problematic infantile hemangioma. However, although rarely, a subset of patients experience undesirable side effects, raising interest in other selective beta-blockers. We present a large case series of 46 infants treated successfully with oral atenolol, a selective beta-1 blocker.

Ocular Intracameral Pharmacokinetics for a Cocktail of Timolol, Betaxolol, and Atenolol in Rabbits.

The mechanisms of drug clearance from the aqueous humor are poorly defined. In this study, a cocktail approach was used to simultaneously determine the pharmacokinetics of three ß-blocker agents after intracameral (ic) injection into the rabbit eyes. Aqueous humor samples were collected and analyzed using LC-MS/MS to determine drug concentrations. Pharmacokinetic parameters were obtained using a compartmental fitting approach, and the estimated clearance, volume of distribution, and half-life values were the following: atenolol (6.44 µL/min, 687 µL, and 73.87 min), timolol (19.30 µL/min, 937 µL, and 33.64 min), and betaxolol (32.20 µL/min, 1421 µL, and 30.58 min). Increased compound lipophilicity (atenolol < timolol < betaxolol) resulted in higher clearance and volume of distributions in the aqueous humor. Clearance of timolol and betaxolol is about 10 times higher than the aqueous humor outflow, demonstrating the importance of other elimination routes (e.g., uptake to iris and ciliary body and subsequent elimination via blood flow).

Effect of beta blocker use and type on hypoglycemia risk among hospitalized insulin requiring patients.

BACKGROUND: Although beta blockers could increase the risk of hypoglycemia, the difference between subtypes on hypoglycemia and mortality have not been studied. This study sought to determine the relationship between type of beta blocker and incidence of hypoglycemia and mortality in hospitalized patients. METHODS: We retrospectively identified non-critically ill hospitalized insulin requiring patients who were undergoing bedside glucose monitoring and received either carvedilol or a selective beta blocker (metoprolol or atenolol). Patients receiving other beta blockers were excluded. Hypoglycemia was defined as any glucose < 3.9 mmol/L within 24 h of admission (Hypo1day) or throughout hospitalization (HypoT) and any glucose < 2.2 mmol/L throughout hospitalization (Hyposevere). RESULTS: There were 1020 patients on carvedilol, 886 on selective beta blockers, and 10,216 on no beta blocker at admission. After controlling for other variables, the odds of Hypo1day, HypoT and Hyposevere were higher for carvedilol and selective beta blocker recipients than non-recipients, but only in basal insulin nonusers. The odds of Hypo1day (odds ratio [OR] 1.99, 95% confidence interval [CI] 1.28, 3.09, p = 0.0002) and HypoT (OR 1.38, 95% CI 1.02, 1.86, p = 0.03) but not Hyposevere (OR 1.90, 95% CI 0.90, 4.02, p = 0.09) were greater for selective beta blocker vs. carvedilol recipients in basal insulin nonusers. Hypo1day, HypoT, and Hyposevere were all associated with increased mortality in adjusted models among non-beta blocker and selective beta blocker recipients, but not among carvedilol recipients. CONCLUSIONS: Beta blocker use is associated with increased odds of hypoglycemia among hospitalized patients not requiring basal insulin, and odds are greater for selective beta blockers than for carvedilol. The odds of hypoglycemia-associated mortality are increased with selective beta blocker use or nonusers but not in carvedilol users, warranting further study.

Postnatal ß2 adrenergic treatment improves insulin sensitivity in lambs with IUGR but not persistent defects in pancreatic islets or skeletal muscle.

KEY POINTS: Previous studies in fetuses with intrauterine growth restriction (IUGR) have shown that adrenergic dysregulation was associated with low insulin concentrations and greater insulin sensitivity. Although whole-body glucose clearance is normal, 1-month-old lambs with IUGR at birth have higher rates of hindlimb glucose uptake, which may compensate for myocyte deficiencies in glucose oxidation. Impaired glucose-stimulated insulin secretion in IUGR lambs is due to lower intra-islet insulin availability and not from glucose sensing. We investigated adrenergic receptor (ADR) ß2 desensitization by administering oral ADRß modifiers for the first month after birth to activate ADRß2 and antagonize ADRß1/3. In IUGR lambs ADRß2 activation increased whole-body glucose utilization rates and insulin sensitivity but had no effect on isolated islet or myocyte deficiencies. IUGR establishes risk for developing diabetes. In IUGR lambs we identified disparities in key aspects of glucose-stimulated insulin secretion and insulin-stimulated glucose oxidation, providing new insights into potential mechanisms for this risk. ABSTRACT: Placental insufficiency causes intrauterine growth restriction (IUGR) and disturbances in glucose homeostasis with associated ß adrenergic receptor (ADRß) desensitization. Our objectives were to measure insulin-sensitive glucose metabolism in neonatal lambs with IUGR and to determine whether daily treatment with ADRß2 agonist and ADRß1/ß3 antagonists for 1 month normalizes their glucose metabolism. Growth, glucose-stimulated insulin secretion (GSIS) and glucose utilization rates (GURs) were measured in control lambs, IUGR lambs and IUGR lambs treated with adrenergic receptor modifiers: clenbuterol atenolol and SR59230A (IUGR-AR). In IUGR lambs, islet insulin content and GSIS were less than in controls; however, insulin sensitivity and whole-body GUR were not different from controls. Of importance, ADRß2 stimulation with ß1/ß3 inhibition increases both insulin sensitivity and whole-body glucose utilization in IUGR lambs. In IUGR and IUGR-AR lambs, hindlimb GURs were greater but fractional glucose oxidation rates and ex vivo skeletal muscle glucose oxidation rates were lower than controls. Glucose transporter 4 (GLUT4) was lower in IUGR and IUGR-AR skeletal muscle than in controls but GLUT1 was greater in IUGR-AR. ADRß2, insulin receptor, glycogen content and citrate synthase activity were similar among groups. In IUGR and IUGR-AR lambs heart rates were greater, which was independent of cardiac ADRß1 activation. We conclude that targeted ADRß2 stimulation improved whole-body insulin sensitivity but minimally affected defects in GSIS and skeletal muscle glucose oxidation. We show that risk factors for developing diabetes are independent of postnatal catch-up growth in IUGR lambs as early as 1 month of age and are inherent to the islets and myocytes.