Impact of study outcome on submission and acceptance metrics for peer reviewed medical journals: six year retrospective review of all completed GlaxoSmithKline human drug research studies

Objectives To determine whether the outcome of drug studies influenced submission and/or acceptance rates for publication in peer reviewed medical journals.Design A six year retrospective review of publication status by study outcome for all human drug research studies conducted by a single industry sponsor (GlaxoSmithKline) that completed from 1 January 2009 to 30 June 2014 and were therefore due for manuscript submission (per the sponsor's policy) to peer reviewed journals within 18 months of study completion-that is, 31 December 2015. In addition, manuscripts from studies completing after 30 June 2014 were included irrespective of outcome if they were submitted before 31 December 2015.Setting Studies conducted by a single industry sponsor (GlaxoSmithKline)Studies reviewed 1064 human drug research studies.Main outcome measures All studies were assigned a publication status at 26 February 2016 including (as applicable): study completion date, date of first primary manuscript submission, number of submissions, journal decision(s), and publication date. All studies were also classified with assessors blinded to publication status as "positive" (perceived favorable outcome for the drug under study), "negative" (perceived unfavorable outcome for the drug under study), mixed, or non-comparative based on the presence and outcome of the primary outcome measure(s) for each study. "Negative" studies included safety studies in which the primary outcome was achieved but was adverse for the drug under study. For the total cohort and each of the four study outcomes, measures included descriptive statistics for study phase, time from study completion to submission and publication, and number and outcome (accepted/rejected) of publication submissions.Results Of the 1064 studies (phase I-IV, interventional and non-interventional) included, 321 had study outcomes classified as positive, 155 as negative, 52 as mixed, and 536 as non-comparative. At the time of publication cut-off date (26 February 2016), 904 (85%) studies had been submitted for publication as full manuscripts and 751 (71%) had been successfully published or accepted, with 100 (9%) still under journal review. An additional 77 (7%) studies were conference abstracts and were not included in submission or publication rates. Submission rates by study outcome were 79% for the 321 studies with positive outcomes, 92% for the 155 with negative outcomes, 94% for the 52 with mixed outcomes, and 85% for the 536 non-comparative studies; while rates of publication at the cut-off date were 66%, 77%, 77%, and 71%, respectively. Median time from study completion to submission was 537 days (interquartile range 396-638 days) and 823 days (650-1063 days) from completion to publication, with similar times observed across study outcomes. First time acceptance rates were 56% for studies with positive outcomes and 48% for studies with negative outcomes. Over 10% of studies across all categories required three or more submissions to achieve successful publication. At the time of analysis, 83 studies had not been submitted for publication, including 49 bioequivalence studies with positive outcomes and 33 non-comparative studies. Most studies (98%, 1041/1064) had results posted to one or more public registers, including all studies subject to FDAAA (Food and Drug Administration Amendments Act) requirements for posting to www.clinicaltrials.govConclusions Over the period studied, there was no evidence of submission or publication bias: 92% of studies with negative outcomes were submitted for publication by the cut-off date versus 79% of those with positive outcomes. Publication rates were slightly higher for studies with a negative (that is, unfavorable) outcome compared with a positive outcome, despite a slightly lower rate of acceptance at first submission. Many studies required multiple submission attempts before they were accepted for publication. Analyses focusing solely on publication rates do not take into account unsuccessful efforts to publish. Sponsors and journal editors should share similar information to contribute to better understanding of issues and barriers to full transparency.

Full central neurokinin-1 receptor blockade is required for efficacy in depression: evidence from orvepitant clinical studies

Full, persistent blockade of central neurokinin-1 (NK1) receptors may be a potential antidepressant mechanism. The selective NK1 antagonist orvepitant (GW823296) was used to test this hypothesis. A preliminary positron emission tomography study in eight male volunteers drove dose selection for two randomized six week studies in patients with major depressive disorder (MDD). Displacement of central [(11)C]GR205171 binding indicated that oral orvepitant doses of 30-60 mg/day provided >99% receptor occupancy for ≥24 h. Studies 733 and 833 randomized patients with MDD and 17-item Hamilton Depression Rating Scale (HAM-D)≥22 to double-blind treatment with orvepitant 30 mg/day, orvepitant 60 mg/day or placebo (1:1:1). Primary outcome measure was change from baseline in 17-item HAM-D total score at Week 6 analyzed using mixed models repeated measures. Study 733 (n=328) demonstrated efficacy on the primary endpoint (estimated drug-placebo differences of 30 mg: -2.41, 95% confidence interval (CI) (-4.50 to -0.31) p=0.0245; 60 mg: -2.86, 95% CI (-4.97 to -0.75) p=0.0082). Study 833 (n=345) did not show significance (estimated drug-placebo differences of 30 mg: -1.67, 95% CI (-3.73 to 0.39) p=0.1122; 60 mg: -0.76, 95% CI (-2.85 to 1.32) p=0.4713). The results support the hypothesis that full, long lasting blockade of central NK1 receptors may be an efficacious mechanism for the treatment of MDD.

Efficacy, safety, and tolerability of a triple reuptake inhibitor GSK372475 in the treatment of patients with major depressive disorder: two randomized, placebo- and active-controlled clinical trials

GSK372475 is a triple reuptake inhibitor with approximately equipotent inhibition of serotonin, norepinephrine, and dopamine transporters. Two randomized, placebo- and active-controlled, double-blind studies examined the efficacy and safety of GSK372475 in outpatients (aged 18-64 years) with a diagnosis of major depressive episode associated with major depressive disorder (MDD). Patients were randomized 1:1:1 to placebo, GSK372475 (1-2 mg/d), or active control (Study 1: venlafaxine XR 150-225 mg/d; Study 2: paroxetine 20-30 mg/d). GSK372475 did not significantly differ from placebo on any of the key efficacy endpoints (six-item Bech scale, IDS-Clinician Rated, MADRS) in either study. Both active controls demonstrated significant antidepressant activity compared with placebo on both primary and secondary endpoints. The most common adverse effects (AEs) with GSK372475 were dry mouth, headache, insomnia, and nausea. AEs were more frequent for GSK372475 versus placebo for sleep, anxiety-related, gastrointestinal, and tachycardia events. Increases in mean change from baseline in heart rate and sitting blood pressure were greater for GSK372475 than observed for either placebo or active control groups. Completion rates were lower for GSK372475 (49%, 58%) compared with placebo (67%, 74%), venlafaxine XR (63%), or paroxetine (77%). GSK372475 was neither efficacious nor well tolerated in patients with MDD in two 10-week studies.

Clinical value of early partial symptomatic improvement in the prediction of response and remission during short-term treatment trials in 3369 subjects with bipolar I or II depression

OBJECTIVE

To evaluate the clinical value of early partial symptomatic improvement in predicting the probability of response during the short-term treatment of bipolar depression.

METHODS

Blinded data from 10 multicenter, randomized, double-blind, placebo-controlled trials in bipolar I or II depression were used to determine if early improvement (≥20% reduction in depression symptom severity after 14 days of treatment) predicted later short-term response or remission. Sensitivity, specificity, efficiency, and positive and negative predictive values (PPV, NPV) were calculated using an intent to treat analysis of individual and pooled study data.

RESULTS

1913 patients were randomized to active compounds (aripiprazole, lamotrigine, olanzapine/olanzapine-fluoxetine, and quetiapine), and 1456 to placebo. In the pooled positive studies, early improvement predicted response and remission with high sensitivity (86% and 88%, respectively), but rates of false positives were high (53% and 59%, respectively). Pooled negative predictive values for response/remission (i.e. confidence in knowing the drug will not result in response or remission) were 74% and 82%, respectively, with low rates of false negatives (14% and 12%, respectively).

CONCLUSION

Early improvement in an individual patient does not appear to be a reliable predictor of eventual response or remission due to an unacceptably high false positive rate. However, the absence of early improvement appears to be a highly reliable predictor of eventual non-response, suggesting that clinicians can have confidence in knowing when a drug is not going to work during short-term treatment. Patients who fail to demonstrate early improvement within the first two weeks of treatment may benefit from a change in therapy.

Double-blind, placebo-controlled comparison of the antidepressant efficacy and tolerability of bupropion XR and venlafaxine XR

Bupropion, a noradrenaline/dopamine reuptake inhibitor, and venlafaxine, a serotonin/noradrenaline reuptake inhibitor, are both established antidepressants with proven efficacy in randomized controlled clinical trials. The objective of this double-blind, randomized, placebo- and active-controlled, eight-week, flexible-dose study was to evaluate the efficacy and tolerability of the once-daily extended-release formulations of these two antidepressants compared with placebo. Patients with major depressive disorder were randomized to once-daily treatment with bupropion XR 150 mg (n = 204), the extended-release formulation of venlafaxine (venlafaxine XR) 75 mg (n = 198) or placebo (n = 189) during weeks 1 to 4, with the option to double the dose at week 5 if response was inadequate. In this study, bupropion XR did not demonstrate statistically significant evidence of greater improvement from baseline compared with placebo on week 8 Montgomery Asberg Depression Rating scale scores (primary endpoint) or on secondary endpoints including CGI, HAM-A and responder and remitter analyses. Descriptive statistics for venlafaxine XR indicated separation versus placebo on MADRS total scores at week 8 and other intermediate time points, and on other endpoints including CGI, HAM-A and responder and remitter analyses. Both active treatments elicited improvement on the Sheehan Disability Scale and its subscales and were generally well tolerated at the doses studied. Rates of nausea, dry mouth, dizziness, hyperhidrosis, insomnia, constipation, tremor, anorexia and male sexual dysfunction were elevated in the venlafaxine XR group, consistent with its mixed serotonergic/noradrenergic mechanism. Rates of dry mouth, insomnia and hyperhidrosis were elevated in the bupropion XR group, consistent with its catecholaminergic mechanism.

Discovery and development of lamotrigine for bipolar disorder: a story of serendipity, clinical observations, risk taking, and persistence

This paper briefly reviews and comments on the development of lamotrigine as a treatment for bipolar disorder. The events described include astute clinical observations by epileptologists, serendipitous coupling of the drug's clinical profile to unmet need of two refractory bipolar patients by a practicing psychiatrist, risk taking on the part of an industry sponsor, and persistence on the part of a few key internal and external advocates to see development through to its conclusion, taking place against a backdrop of a disease area which, at the time of the earliest events described here, had not seen the development of any new pharmacologic treatments for decades. Fortunately for patients, since that time there has been a veritable explosion of research into treatments for bipolar disorder, both old and new, so that now patients and physicians have multiple evidence-based options for the treatment of this devastating illness. The development of lamotrigine provides one example of the importance of prescience, patience and persistence in bringing a novel idea to clinical fruition.

Maintenance treatment outcomes in older patients with bipolar I disorder

OBJECTIVE

The efficacy and tolerability of mood stabilizers in older adults with bipolar disorder remains understudied. Authors retrospectively examined response to lamotrigine, lithium, and placebo in older (>or=age 55) adults with Bipolar I disorder (DSM-IV) who participated in two mixed-age, maintenance studies examining time to intervention for an emerging mood episode (manic/hypomanic/mixed or depressed) and drug tolerability.

METHODS

In all, 588 patients received double-blind lamotrigine (LTG, 100 mg-400 mg/day), lithium (Li, 0.8 mEq/L-1.1 mEq/L), or placebo (PBO); data from 98 older adults (LTG: 33, Li: 34, PBO: 31) were examined. Mean modal total daily doses were LTG 240 mg and Li 750 mg.

RESULTS

LTG significantly delayed time to intervention for any mood episode and for a depressive episode, compared with placebo. Li significantly delayed time to intervention for mania/hypomania/mixed compared with placebo. Back pain and headache were the most common adverse events during LTG treatment; rash: LTG, 3%; Li, 6%; and PBO, 0; no serious rash was reported. The most common adverse events (>10%) during lithium treatment were dyspraxia, tremor, xerostomia, headache, infection, amnesia, dizziness, diarrhea, nausea, and fatigue.

CONCLUSION

Lamotrigine and lithium may be effective and well-tolerated maintenance therapies for older adults with Bipolar I depression.

The effect of bupropion on nicotine craving and withdrawal

RATIONALE AND OBJECTIVES

Bupropion has demonstrated efficacy for smoking cessation. Given the importance of nicotine craving and withdrawal in the smoking cessation process, the current study examined the effects of bupropion on these parameters during smoking abstinence.

METHODS

During a 2-day Baseline phase with ad lib smoking, 91 non-depressed smokers (who were not trying to quit permanently) were administered measures of nicotine craving, withdrawal symptoms, and timed measures of cognitive performance five times daily. Participants were then assigned randomly to a 14-day treatment regimen with bupropion 300 mg/day, bupropion 150 mg/day, or placebo. Thereafter, the above measures were re-administered during 3 days of abstinence on a closed research ward.

RESULTS

Relative to placebo, 300 mg bupropion significantly reduced abstinence-associated increases in rated depression, difficulty concentrating, and irritability, and attenuated a decrease in positive affect. The results also suggested that bupropion might have a positive effect on performance measures during the withdrawal period. No effects were observed on craving, anxiety, restlessness, or hunger. The lack of findings on craving measures may be explained by a floor effect; except on the first day of abstinence, neither drug nor placebo groups showed much craving elevation during abstinence.

CONCLUSIONS

Study results indicate that bupropion ameliorates some nicotine withdrawal symptoms.

Ultraviolet irradiation selectively disrupts the gamma-aminobutyric acid/benzodiazepine receptor-linked chloride ionophore

The ability of UV light to affect radioligand binding and 36Cl-uptake at the gamma-aminobutyric acidA (GABAA) receptor-chloride channel complex was examined. Exposure to 302 nm UV light produced a rapid (t1/2 = 4 min) reduction in [35S]t-butylbicyclo-phosphorothionate binding (assayed in the presence of 200 mM chloride) to sites associated with the GABAA receptor-coupled chloride ionophore. Saturation analysis revealed that this effect could be attributed entirely to a decrease in the maximum number of binding sites. Exposure to UV irradiation at lower (254 nm) and higher (366 nm) wavelengths also inhibited [35S]t-butylbicy-clophosphorothionate binding, but the respective rates of inactivation were 8- and 27-fold slower, compared with 302 nm. Other anion-dependent interactions at the GABAA receptor complex were disrupted in a similar manner. In the absence of permeant anion, [3H]flunitrazepam binding to benzodiazepine receptors was unaffected by 302 nm UV irradiation, whereas chloride-enhanced [3H]flunitrazepam binding was inhibited markedly. In the presence of 250-500 mM chloride, [3H]methyl-6,7-dimethoxy-4-ethyl-beta-carboline-3-carboxylate binding to benzodiazepine receptors was also inhibited after UV exposure. Basal 36Cl- uptake into synaptoneurosomes was nearly doubled after 15 min of exposure to 302 nm light, whereas pentobarbital- and muscimol-stimulated 36Cl- uptake were reduced significantly. UV irradiation at 302 nm appears to disrupt selectively the anion-dependent functional interactions at the GABAA receptor complex. The apparent wavelength specificity suggests that the gating structure (channel) may contain tryptophan and/or tyrosine residues vital to the regulation of anion movement through the ionophore portion of this supramolecular receptor-ion channel complex.

Effects of running the Boston marathon on plasma concentrations of large neutral amino acids

Plasma large neutral amino acid concentrations were measured in thirty-seven subjects before and after completing the Boston Marathon. Concentrations of tyrosine, phenylalanine, and methionine increased, as did their "plasma ratios" (i.e., the ratio of each amino acid's concentration to the summed plasma concentrations of the other large neutral amino acids which compete with it for brain uptake). No changes were noted in the plasma concentrations of tryptophan, leucine, isoleucine, nor valine; however, the "plasma ratios" of acid patterns may influence neurotransmitter synthesis.

Picrate and niflumate block anion modulation of radioligand binding to the gamma-aminobutyric acid/benzodiazepine receptor complex

The organic anions picrate (2,4,6-trinitrophenol) and niflumate (2-[[3-(trifluoromethyl)phenyl]-amino]-3-pyridinecarboxylate) were examined for their effects on radioligand binding to the gamma-aminobutyric acid (GABA)/benzodiazepine receptor complex. Neither organic anion produced the enhancement of [35S] t-butylbicyclophosphorothionate (TBPS) binding characteristic of anions (such as Cl- and Br-) known to permeate GABA-gated chloride channels. However, both picrate and niflumate potently (IC50 values between 66 and 531 and 30 and 155 microM, respectively) inhibited the effect of 100-200 mM concentrations of anions (I-, Br-, Cl-, SCN-, and F-) to increase the binding of [35S]TBPS to GABA-gated chloride channels. This inhibition resulted from a decrease in both the maximum number of binding sites and the apparent affinity (increased Kd) of [35S]TBPS. Niflumate was consistently more potent than picrate, but both organic anions exhibited the same sequence of relative potencies against smaller anions (I- greater than Br- greater than Cl- greater than SCN- greater than F-). This sequence was similar to that described for the relative permeabilities of these anions through GABA-gated chloride channels. Niflumate and picrate were potent inhibitors of Cl-, but not GABA-modulated radioligand binding to benzodiazepine receptors. These findings suggest that picrate and niflumate bind with high affinity at or near an anion binding site that may regulate the movement of anions through GABA-gated chloride channels and radioligand binding at this "supramolecular complex."

Anion regulation of agonist and inverse agonist binding to benzodiazepine receptors

Binding of the benzodiazepine inverse agonist [3H]methyl-6,7-dimethoxy-4-ethyl-beta-carboline-3-carboxylate [( 3H]DMCM) and the agonist [3H]flunitrazepam [( 3H]FNZ) was compared in rat cortical membranes. Halide ions enhanced [3H]DMCM binding three- to fourfold, increasing both the apparent affinity and the number of binding sites for this radioligand. The effect was present at both 0 and 37 degrees C. In contrast, the magnitude of halide stimulation of [3H]FNZ binding was much smaller, resulting solely from an increase in the apparent affinity for this radioligand, and was not observed at 37 degrees C. The potencies but not the efficacies of a series of anions to stimulate both [3H]DMCM and [3H]FNZ binding to benzodiazepine receptors were highly correlated with their relative permeabilities through gamma-aminobutyric acid (GABA)-gated chloride channels. Two stress paradigms (10 min of immobilization or ambient-temperature swim stress), previously shown to increase significantly the magnitude of halide-stimulated [3H]FNZ binding, did not significantly affect [3H]DMCM binding. Phospholipase A2 treatment of cortical membrane preparations was equipotent in preventing the stimulatory effect of chloride on both [3H]DMCM and [3H]FNZ binding. These data strongly suggest that anions modify the binding of [3H]DMCM and [3H]FNZ by acting at a common anion binding site that is an integral component of the GABA/benzodiazepine receptor chloride channel complex.

Endogenous adenosine and hemorrhagic shock: effects of caffeine administration or caffeine withdrawal

Plasma adenosine concentrations doubled when rats were subjected to 90 min of profound hemorrhagic shock. Administration of caffeine (20 mg per kg of body weight), an adenosine-receptor antagonist, attenuated the hemorrhage-induced decrease in blood pressure. In contrast, chronic caffeine consumption (0.1% in drinking water), followed by a brief period of caffeine withdrawal, amplified the hypotensive response to hemorrhage. These data suggest that endogenous adenosine participates in the hypotensive response to hemorrhage and that caffeine may protect against, and caffeine withdrawal may exacerbate, this response.

A1- and A2-selective adenosine antagonists: in vivo characterization of cardiovascular effects

Caffeine, a nonselective adenosine receptor antagonist, 7-methyl-1,3-dipropylxanthine, a purported A2 selective antagonist and a 1,3-dipropyl-8-phenylxanthine amine congener (XAC), an A1 selective antagonist, were evaluated for their in vivo selectivity at A1 vs. A2 adenosine receptors. Blockade of the negative chronotropic effect of bolus i.v. injections of 2-chloroadenosine, R-phenylisopropyladenosine and N-ethylcarboxamidoadenosine was utilized as an index of antagonism at A1 receptors; blockade of the hypotensive effect of the same series of adenosine agonists was used as an index of activity at A2 receptors. In addition, blockade of the potentiating effect of adenosine on the hypertensive and chronotropic effects of nicotine was studied to assess further the role of A1 and A2 adenosine receptors in this response. The potent antagonist XAC displayed considerable A1 selectivity as demonstrated by blockade of adenosine receptor-mediated bradycardia at doses 5- to 10-fold lower than those antagonizing adenosine receptor-mediated hypotension. XAC also selectively blocked potentiation by adenosine of the positive chronotropic effect of nicotine, at doses which had minimal effects on the enhancement of the hypertensive effect of nicotine. The caffeine homolog 7-methyl-1,3-dipropylxanthine exhibited A2 selectivity as demonstrated by prevention of adenosine receptor-mediated hypotension at doses which only minimally attenuated the bradycardiac effect of adenosine analogs. Caffeine displayed no selectivity for A1 vs. A2 adenosine receptors. The results indicate that selective analogs such as XAC and F-methyl-1,3-dipropylxanthine will be useful probes for investigation of receptors involved in the physiological functions of adenosine.

Antagonism of the cardiovascular effects of adenosine by caffeine or 8-(p-sulfophenyl)theophylline

We compared the abilities of the adenosine antagonists caffeine and 8-(p-sulfophenyl)theophylline (8-SPT) to block adenosine receptor-mediated hypotension and bradycardia in anesthetized rats. Few quantitative data exist concerning the amounts of caffeine needed to prevent the cardiovascular effects of physiologic plasma adenosine concentrations or concerning the site of action (central or peripheral) of such blockade. Thus, dose-response curves were constructed for the antagonism by caffeine or 8-SPT of the hypotension and bradycardia caused by infusing adenosine i.v. or by giving bolus i.v. injections of the adenosine analogs 2-chloroadenosine, R-phenylisopropyladenosine or N-ethylcarboxamidoadenosine. We also quantitated the suppression by caffeine or 8-SPT of the ability of adenosine to potentiate nicotine-induced hypertension and tachycardia. Caffeine (EC50 = 92 microM) and 8-SPT (EC50 = 48 microM) blocked the hypotension produced by elevating plasma adenosine levels from 1.22 to 1.74 microM. Similar drug doses were needed to inhibit the potentiation by adenosine of pressor and chronotropic responses to nicotine or to antagonize the hypotensive and negative chronotropic effects of 2-chloroadenosine, R-phenylisopropyladenosine and N-ethylcarboxamidoadenosine. As expected, neither caffeine nor 8-SPT demonstrated selectivity for A1 (predominating at the heart) vs. A2 (predominating at blood vessels) receptor subtypes. Administration of as much as 50 mg/kg i.p. of 8-SPT failed to produce detectable brain levels of the drug, demonstrating its failure to gain access to the central nervous system and indicating that the site at which the drug antagonizes the cardiovascular effects of adenosine is peripheral.(ABSTRACT TRUNCATED AT 250 WORDS)

Hepatic cyclic AMP generation and ornithine decarboxylase induction by glucagon and beta adrenergic agonists

The relationship of hepatic ornithine decarboxylase (ODC) activity to cyclic AMP levels and nutritional status was studied in the pre-weanling rat. Previous studies demonstrated that 2 hr without food causes a loss of hepatic ODC induction after glucagon or catecholamine injection. Isoproterenol or glucagon administration produced increased hepatic cyclic AMP and tyrosine aminotransferase activity which were not prevented by nutritional deprivation. Blockade of hepatic beta 2 receptors by the selective antagonist ICI 118,551 prevented increased cAMP levels and ODC activity after isoproterenol administration. Blockade of beta 1 receptors by atenolol did not prevent increased cAMP levels or ODC induction by isoproterenol although it did block activation of cardiac ODC. The phosphodiesterase inhibitor RO20-1724 increased hepatic cAMP levels as well as ODC and TAT activities, although the increase in ODC activity was attenuated by nutritional deprivation. RO20-1724 also potentiated the induction of hepatic ODC after glucagon or isoproterenol administration. Administration of 8-bromo cAMP elevated hepatic ODC activity regardless of nutritional status but also elevated serum levels of growth hormone and corticosterone. Hepatic ODC induction by glucagon or beta 2 agonists can be dissociated from changes in cAMP levels during nutritional deprivation.

Intrahepatic glucose: a requirement for neonatal ODC induction by specific hormones

We have shown previously that short-term nutritional deprivation causes a tissue-specific loss of liver ornithine decarboxylase (ODC) induction after isoproterenol, phenylephrine, or glucagon administration in rat pups. To examine the role of nutrition in the regulation of hepatic ODC, we tested the ability of intragastric nutrient administration to reverse nutritionally related deficits in the ODC response to hormonal challenge. Intragastric whole milk was effective in restoring ODC induction and accumulation of its immediate product, putrescine, in response to isoproterenol administration. Glucose was shown to mediate this effect by the ability of intragastric skimmed milk, lactose, galactose, or D-glucose to return ODC induction, and the inability of casein, sucrose, fructose, L-glucose, or pyruvate plus lactate to do so. D-Glucose also reestablished ODC induction by phenylephrine and glucagon. Parenteral administration of D-glucose produced results comparable to those obtained after intragastric administration. Isoproterenol induction of ODC was prevented when hepatic glucose uptake was blocked by phlorizin but not by blockade of central nervous system glucose uptake with 2-deoxyglucose. We conclude that intrahepatic glucose is an absolute requirement for hepatic ODC induction by isoproterenol, phenylephrine, or glucagon in preweanling rats.