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Biomedical subjects

D R Feller

Publications and source records attributed to D R Feller.

At least 109 records · Page 6Linked to original sources
PubMed1978

Diethyl (4baalpha,4calpha,9aalpha,9balpha)-3,6-dichlorocyclobuta[1,2-b:3,4-b']bisbenzofuran-9a,9b(4bH,4cH)-dicarboxylate: the cis,syn photodimer of ethyl 5-chlorobenzofuran-2-carboxylate, an analogue related to the antilipidemic drug clofibrate.

The antilipidemic properties of diethyl (4balpha,4calpha,9aalpha,4balpha)-3,6-dichlorocyclobutal[1,2-b:3,4-b']bisbenzofuran-9a,9b(4bH,4cH)-dicarboxylate, herein termed dimer 8, were studied in sucrose-fed and in Triton-induced hyperlipidemic rats. Whereas clofibrate (0.4 mmol/kg) exhibited both anticholesterolemic and antitriglyceridemic activity, dimer 8 showed only antitriglyceridemic properties at the lower dose (0.2 mmol/kg) in sucrose-fed rats. Dimer 8 only lowered serum triglycerides levels in Triton WR-1339 hyperlipidemic rats, whereas clofibrate lowered both cholesterol and triglyceride levels. In the chronic sucrose-fed model, dimer 8 and clofibrate lowered hepatic HMG-CoA reducatase activity and produced significant elevations in several parameters of hepatic drug metabolism. No positive relationship between serum cholesterol lowering and reduction of hepatic HMG-CoA reductase activity was observed by these agents in sucrose-fed rats.

Animals↗
PubMed1978

Synthesis and beta-adrenoceptor activity of the erythro and threo isomers of substituted alpha-hydroxytrimetoquinol.

The synthesis and pharmacological activity of erythro and threo isomers of 1-(3',4',5'-trimethoxy-alpha-hydroxy-benzyl)-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline, 2 and 3, are reported. The structural assignments of 2 and 3 are based upon NMR spectra of the 6,7-dibenzyl precursors, 6 and 10, and of the synthetic derivatives of 13alpha- and 13beta-hydroxy-2,3-(dibenzyloxy)-9,10,11-trimethoxytetrahydroprotoberberine, 8 and 12, respectively. The erythro isomer 2 was a more potent beta-adrenoceptor stimulant than the threo isomer 3 in guinea pig atrial, guinea pig tracheal, and rat adipocyte preparations. The differential activity of these compounds on lipolysis was favorably correlated to changes in the stimulation of adenylate cyclase activity and cAMP accumulation in rat adipocytes.

Adipose Tissue↗
PubMed1978

Synthesis and pharmacological evaluation of a clofibrate-related tricyclic spirolactone, 5-chloro-4',5-dihydrospiro[benzofuran-2(3H),3'(2'H)-furan]-2'-one.

The chemistry and pharmacology of the title compound, spirolactone 4, are reported. The synthesis represents a new approach to the preparation of spiro compounds. The pharmacological profiles of 4 are compared to that of clofibrate in Triton-induced hyperlipidemic, sucrose-fed, and normal Sprague-Dawley rat models. Clofibrate was effective in all animal models, but the spirolactone 4 exhibited antitriglyceridemic activity only in the Triton model. The inactivity of 4 in sucrose- and chow-fed rats could not be attributed to a resistance to hydrolysis by serum esterases. Comparative studies revealed that inhibition of hepatic HMG-CoA reductase activity may not be an index of hypocholesterolemic action in sucrose-fed rats. Additionally, only clofibrate exhibited significant changes in components of the hepatic microsomal monooxygenase system.

Animals↗
PubMed1977

Comparison of hypocholesterolemic activity for cyclic analogs of clofibrate in normolipemic rats.

Chronic administration of ethyl 2-methyl-2(4-chlorophenoxy)-propionate [clofibrate, CPIB], ethyl 6-cyclohexylchroman-2carboxylate, and ethyl 6-phenylchroman-2-carboxylate to normolipemic rats, in vivo, reduced serum cholesterol levels and inhibitid the activiry of hepatic 3-hydroxy-3methyl-glutaryl Coenzyme A. Only clofibrate was found to lower liver cholesterol content after pretreatment for 4 or 18 days. The cyclic analogs, ethyl 6-cholorochromone-2-carboxylate and 9-chloro-2,3-dihydro-5H-1,4-dioxepino [6,5-b] benzofuran were inaffective as cholesterol lowering agents in normolipemic rats. These findings indicate that appropriate modification of clofibrate can lead to the development of compounds which are selective and equally effective to clofibrate as potential hypocholesterolemic agents. Results obtained in these studies are also discussed in terms of the known structural requirements of biological activity for this series of cyclic analogs in the Triton WR-1339 hyperlipemic rat model and modes of action of the parent compound.

Animals↗
PubMed1977

Synthesis and biological evaluation of a tetrahydroisoquinoline derivative possessing selective beta2-adrenergic agonist activity.

This paper reports the synthesis of 4-(3,4,5-trimethoxybenzyl)-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline (2) and 2-(3,4-dihydroxyphenyl)-3-(3,4,5-trimethoxyphenyl)propylamine (3). The biological activity of these agents relative to that of trimetoquinol (1) in guinea pig atria and guinea pig trachea is reported. The relative activities in relaxation of guinea pig trachea is 1 greater than 2 greater than 3 while in the chronotropic response in guinea pig atria the relative order of activity is 1 greater than 3 greater than 2.

Adrenergic beta-Agonists↗
PubMed1977

Synthesis of 1-substituted analogues of trimetoquinol possessing differential and selective beta-adrenergic properties.

The synthesis of the 1,1-disubstituted tetrahydroisoquinoline analogues, 1-methyl-1-(3,4,5-trimethoxybenzyl)-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline hydrochloride (2) and 1-benzyl-1-(3,4,5-trimethoxybenzyl)-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline hydrochloride (3), is described. The profile of beta-adrenergic activity for these analogues was determined and compared to that of trimetoquinol (1) in isolated guinea pig atrial, tracheal, and rat adipocyte preparations. Unexpected selective beta1-blocking activity in guinea pig trachea was noted with analogue 3. With the exception of 2 in guinea pig atria, 2 and 3 did not possess any beta-stimulant activity. Substitution at the 1 position of trimetoquinol (1) has revealed qualitative differences in beta-adrenergic activity.

Adipose Tissue↗
PubMed1976

Synthesis and antilipidemic properties of cis-7-chloro-3a, 8b-dihydro-3a-methylfuro[3,4-b]benzofuran-3(1H)-one, a tricyclic clofibrate related lactone having a structural resemblance to mevalonolactone.

The synthesis for the title lactone 2, designed to be an antagonist of the enzyme HMG-CoA reductase (E.C.1.1.1.34), is described. Lactone 2, its synthetic tricyclic hemiacetal precursor 4, and clofibrate were investigated for their antilipidemic activity in 7-day treated normal and in Triton WR-1339 induced hyperlipidemic male Sprague-Dawley rats. After 7-day drug administration to normal rats, lactone 2 was less effective than clofibrate in lowering HMG-CoA reductase activity and serum cholesterol; however, unlike clofibrate, lactone 2 did not increase liver weight or liver-body weight ratio or lower serum triglycerides. Since hemiacetal 4 selectively influenced triglycerides in normal animals, lactone 2 and hemiacetal 4 appear to have differential hypolipidemic effects. In the Triton hyperlipidemic model 2 and 4 lowered elevated triglycerides; only 4 significantly reduced elevated cholesterol levels; but neither 2 nor 4 was as effective as clofibrate. Differences in the observed antilipidemic properties for clofibrate, 2, and 4 in the two animal models are discussed. On the basis of preliminary biological data described in this article it is concluded that tricyclic analogues 2 and 4 represent reasonable leads for the development of new antilipidemic agents.

Animals↗
PubMed1976

Phosphodiesterase inhibition and lipolytic action of the stereoisomers of trimetoquinol.

The isomers and racemate of trimetoquinol [TMQ; 6-7-dihydroxy-1-(3',4',5'-trimethoxybenzyl)-1,2,3,4-tetrahydroisoquinoline] as well as N-(3',4',5'-trimethoxyphenethyl)dopamine were all shown to be effective at promoting glycerol release from rat epididymal fat tissue. The rank order of potency observed for these compounds was (-)-TMQ greater than or equal to (+/-)-TMQ greater than greater than (+)-TMQ = N-(3',4',5-trimethoxyphenethyl)dopamine. (+/-)-TMQ and (-)-TMQ were the only agents capable of producing a maximal lipolytic response. None of the compounds tested were able to exhibit significant c-AMP phosphodiesterase inhibition. This study is the first report which shows that the beta-adrenoceptor activity of the isomers of TMQ does not correlate with an inhibition of c-AMP phosphodiesterase. An alternate mechanism of action for these compounds is proposed.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1976

Metabolic reduction of naltrexone II. In vitro studies using liver from guinea pig, monkey and rat.

Naltrexone was incubated with the 9000 X g supernatant of guinea pig liver in the presence of an NADPH-generating system to determine the relative amounts of the 6-keto reduction products, alpha- and beta-naltrexol, formed in vitro. After a 0.5-2 hour period both alpha- and beta-naltrexol were formed as detected by electron capture gas chromatography of pentafluoropropionic anhydride-derivatized extracts of the incubation mixture. The identity of alpha-naltrexol was confirmed by nuclear magnetic resonance, infrared and mass spectra, as well as by mixed melting point determination. The percentage of natrexol found as the alpha-epimer ranged from 36-81% and was concentration-dependent at substrate concentrations ranging from 0.0007-0.1 mM. The hepatic enzyme(s) responsible for the reduction of naltrexone were localized in the 105,000 X g supernatant fraction of guinea pig liver. In contrast to results obtained for the reduction of naltrexone using guinea pig liver, the 9000 X g and 105,000 X g supernatant fractions of monkey liver appeared to reduce naltrexone almost exclusively to beta-naltrexol. The 9000 X g supernatant of rat liver was less active than similar preparations from guinea pig or monkey liver; only a small amount of beta-naltrexol and no detectable alpha-naltrexol was formed after two hours of incubation. Incubation of the naltrexone metabolites, alpha- or beta-naltrexol, with the 9000 X g supernatant of guinea pig liver and incubation of alpha-naltrexol with guinea pig kidney slices yielded no evidence of interconversion of these metabolites.

Animals↗
PubMed1976

Effect of phenylbutazone on the metabolic disposition of warfarin in the dog.

Phenylbutazone has been shown to modify the physiologic disposition of warfarin in the dog. Dogs pretreated with phenylbutazone for a week, and permitted to remain drug-free for an additional week, eliminated warfarin from plasma 2-3 times faster than non-pretreated controls with an average half-life of 7.8 hours. In-vitro hepatic microsomal metabolism of warfarin and cytochrome P-450 content were greater for hepatic microsomes derived from phenylbutazone pretreated animals.

Animals↗
PubMed1975

Synthesis and biological evaluation of fragmented derivatives of tetrahydroisoquinolines. 2. Trimetoquinol studies.

The synthesis of N-(3',4',5'-trimethoxyphenylethyl)-3,4-dihydroxyphenylethylamine (2) and 1-(3,4,5-trimethoxybenzyl)-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline (1) is presented. Comparative pharmacological effects of the optical isomers of 1 and compound 2 are reported in guinea pig atria, rat adipose tissue, guinea pig trachea, and guinea pig aortic strip preparations. In the beta-adrenoreceptor preparations, (-)-1 was shown to be more potent than (+)-1 or 2. Racemic 1 and 2 were shown to have equal alpha-antagonist properties in the inhibition of norepinephrine-induced contractions of guinea pig aorta.

Adipose Tissue↗
PubMed1975

9-Chloro-2,3-dihydro-5H-1,4-dioxepino(6,5-b)benzofuran, a novel antilipidemic agent structurally related to clofibrate.

The synthesis and antilipidemic activity of 9-chloro-2,3-dihydro-5H-1,4-dioxepino[6,5-b]benzofuran (3), a novel enol lactone which is considerably more resistant to serum esterase hydrolysis than clofibrate (1), are discussed. Whereas both 3 and 1 reduced hypercholesterolemic and hypertriglyceridemic serum levels in the Triton WR-1339 induced hyperlipidemic Sprague-Dawley rat to normal, the hydrolysis product of 3, namely 5-chloro-3(2'-hydroxyethoxy)-2-benzofurancarboxylic acid (4), was found to be inactive. Further, 3 is comparable to the hydrolysis product of 1 when both were assessed for their ability to block norepinephrine (NE) induced lipolysis in vitro. 4 is inactive at comparable concentrations (5 times 10(-4)-10(-3) M). The antilipidemic action of 3 and 1 may, in part, be due to their ability to block NE-induced lipolysis.

Adipose Tissue↗