151
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Marselos M, Törrönen R, Alakuijala P, Macdonald E. Hepatic hydroxylation and glucuronidation in the rat after subacute pyrazole treatment. Toxicology 1977; 8:251-61. [PMID: 412278 DOI: 10.1016/0300-483x(77)90013-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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152
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Becker KE, Ho IK. Pentobarbital distribution in discrete brain areas of tolerant and nontolerant mice. RESEARCH COMMUNICATIONS IN CHEMICAL PATHOLOGY AND PHARMACOLOGY 1977; 18:23-8. [PMID: 905631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Uptake and distribution of pentobarbital in tolerant and nontolerant mice were studied. Mice were implanted with pentobarbital or placebo pellets s.c. 3 days prior to the injection of 60 mg/kg sodium pentobarbital i.p. One group of animals was sacrificed when they first awakened. Whole brain, five discrete brain areas, and plasma were assayed for pentobarbital by gas chromatography. In a second group, time studies were performed on brain sections and plasma. In tolerant vs nontolerant animals, sleeping time was markedly decreased (10-20 vs 50-70 min); whole brain, brain sections, and plasma levels on awakening were not significantly different; linear and exponential curves of pentobarbital levels vs time showed an increase in slope (-1.05 vs-0.40) and a decrease in T 1/2 (10.2 VS 35.7 min). These findings suggest that the tolerance development to pentobarbital in the central nervous system is due to functional mechanism rather than brain dispositional mechanism.
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153
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Shin T, Nakamura S, Shigematsu A. Macroautoradiographic study of the distribution and excretion of 14C-pentobarbitone in rats pretreated with phenobarbitone. Br J Anaesth 1977; 49:847-53. [PMID: 911584 DOI: 10.1093/bja/49.9.847] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The distribution and excretion of pentobarbitone were studied, using macroautoradiography, in two groups of rats at times ranging from 1 min to 70 min after the i.v. injection of 100 muCi given as 30 mg/kg of 14C-pentobarbitone. In a control group, the carbon-14 concentration (concentration of pentobarbitone) in the brain remained always greater than that in heart blood (unchanged pentobarbitone and metabolites). In a group subjected to enzyme induction (pretreated with phenobarbitone), however, the carbon-14 concentration in the brain exceeded that in the heart blood initially and then decreased rapidly. In the induced group, the carbon-14 concentration in the urine and small intestine (almost all of which was metabolites) increased with time. In particular, 70 min after the injection, the carbon-14 concentration in the small intestine of the induction group was twice that of the control group. It was concluded that in the induction group the rapid decrease in carbon-14 concentration in the brain was mainly a result of an increase in the metabolic breakdown of pentobarbitone in the liver.
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154
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Benowitz NL, Jones RT. Effects of delta-9-tetrahydrocannabinol on drug distribution and metabolism. Antipyrine, pentobarbital, and ethanol. Clin Pharmacol Ther 1977; 22:259-68. [PMID: 891094 DOI: 10.1002/cpt1977223259] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Delta-9-tetrahydrocannabinol (THC) has been reported to inhibit drug metabolism in animals. Twenty-two hospitalized healthy volunteer subjects received THC, 60 to 180 mg/day in divided doses for 14 days. Body weight increased and plasma proteins decreased in all subjects, which is consistent with previously reported plasma volume expansion. Total bilirubin was significantly lower, while other liver function tests remained normal. A within-subject comparison of the pharmacokinetics of antipyrine, pentobarbital, or ethanol given before, during, and after THC was performed. Antipyrine plasma half-life increased during THC in 5 of 6 subjects--mean, 7.9 hr +/- 3.3 (SD) to 9.6 +/- 3.8. Pentobarbital half-life increased in 7 of 8 subjects--mean, 16.9 hr +/- 2.0 to 20.8 +/- 4.2. Blood ethanol disappearance rate decreased in 7 of 8 subjects from a mean of 0.26 mg/100 ml/min +/- 0.05 to 0.23 +/- 0.07. The effect of THC on disappearance rate of these drugs appeared to be due to a combination of: (1) increased distribution volume, due in part to expansion of extracellular fluid volume noted during THC ingestion, and (2) diminished metabolic clearance. THC also delayed absorption of pentobarbital and ethanol in several subjects. This is consistent with THC effects of slowing intestinal motility in animals. The effects of THC on absorption and drug elimination must be considered in evaluating interactions with other drugs.
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155
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Kozlowski KH, Szaykowski A, Danysz A. Dependence of pentobarbital kinetics upon the dose of the drug and its pharmacodynamic effects. POLISH JOURNAL OF PHARMACOLOGY AND PHARMACY 1977; 29:497-508. [PMID: 593966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Pentobarbital (PB), at dose range of 20--50 mg/kg, displays in rabbits non-linear, dose-dependent kinetics. Pharmacokinetics parameters of drug elimination depend largely upon the dose, while the distribution phase is dose-independent. The rate of disappearance of PB from the central compartment (plasma) decreases with the increase of the dose. The analysis of pharmacodynamic parameters has shown that this dose-dependent retardation of PB elimination is probably caused by an impairment of metabolic processes, resulting from disturbance of the circulatory system. A close correlation has been found between the hypotensive effect of PB and the elimination constant, k13, and also between the hypotensive effect and beta.Vd(extrap), a coefficient proportional to the rate of metabolism of PB [23, 29]. The results indicate the necessity of considering the changes in the functional state of the organism, related to the action of a drug, in pharmacokinetic studies.
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156
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157
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Bruckner JV, Jiang WD, Brown JM, Putcha L, Chu CK, Stella VJ. The influence of ingestion of environmentally encountered levels of a commercial polychlorinated biphenyl mixture (Aroclor 1254) on drug metabolism in the rat. J Pharmacol Exp Ther 1977; 202:22-31. [PMID: 406382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
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158
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Nemeroff CB, Bissette G, Prange AJ, Loosen PT, Barlow TS, Lipton MA. Neurotensin: central nervous system effects of a hypothalamic peptide. Brain Res 1977; 128:485-96. [PMID: 406965 DOI: 10.1016/0006-8993(77)90173-1] [Citation(s) in RCA: 214] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The central administration of neurotensin, an endogenous hypothalamic tridecapeptide, produces a marked dose-related decrease in body temperature of mice and rats at an ambient temperature of 25 degrees C. This effect is even more pronounced when mice are placed at 4 degrees C to increase the rate of decline of body temperature. Other sequelae observed after central administration of neurotensin are decreases in locomotor activity in rats and a marked dose-related enhancement in pentobarbital-induced mortality, sedation and hypothermia. This latter effect was shown to be due to a significant reduction in the metabolic degradation of the barbiturate. None of the above-mentioned effects are observed after peripheral neurotensin administration, suggesting that this peptide does not readily cross the blood-brain barrier. Neurotensin appears to be one of a growing list of neuropeptides that can affect CNS function.
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159
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Gupta PK, Gupta RC. Effect of endosulfan pretreatment on organ weights and on pentobarbital hypnosis in rats. Toxicology 1977; 7:283-8. [PMID: 888146 DOI: 10.1016/0300-483x(77)90048-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The effects of endosulfan on the weights of the liver, adrenal and ovary, on pentobarbital blood and brain levels and on sleeping time (ST) have been investigated in female rats after daily oral doses of 0, 1.0, 2.5 and 5.0 mg/kg for a period of 7 or 15 days. No significant change in body weight was observed. With higher doses (2.5--5.0 mg/kg) the liver weight was significantly increased, but ovary and adrenal weights did not increase. Endosulfan treatment shortened sleeping time, while induction time was significantly increased. The concentration of pentobarbital in the blood and brain of rats after 30 min and upon awakening indicated that there was a significant decrease at 30 min. No change at awakening was observed in endosulfan-treated rats as compared to controls. It is suggested tha endosulfan may shorten the duration of pentobarbital-induced sleep, perhaps by induction of hepatic microsomal enzyme activity.
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160
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Ossenberg FW. [Pharmacokinetics of pentobarbital in liver damage]. ZEITSCHRIFT FUR GASTROENTEROLOGIE 1977; 15:393-403. [PMID: 888490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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161
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Di Gregorio GJ, Piraino AJ, Nagle BT, Knaiz EK. Secretion of drugs by the parotid glands of rats and human beings. J Dent Res 1977; 56:502-8. [PMID: 267105 DOI: 10.1177/00220345770560051001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The following drugs have been demonstrated to be secreted by the parotid glands of rats and human beings: amobarbital, chlorpromazine, codeine, glutethimide, meprobamate, pentobarbital, phenobarbital, and secobarbital. Methadone could not be detected in the parotid saliva of either rats or human beings, and morphine has been demonstrated only in parotid saliva of rats.
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162
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Borodkin S, Macy L, Thompson G, Schmits R. Stable nonaqueous pentobarbital sodium solutions for use in laboratory animals. J Pharm Sci 1977; 66:693-5. [PMID: 874753 DOI: 10.1002/jps.2600660521] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The degradation kinetics of pentobarbital sodium in propylene glycol-based solutions were studied along with the in vivo effects in laboratory animals. The degradation rate constant was directly proportional to the water concentration in propylene glycol-water solvent systems. An activation energy of 23.4 kcal/mole was obtained in propylene glycol-water (1:1). Pentobarbital sodium solutions in anhydrous propylene glycol and 9:1 mixtures of propylene glycol with ethanol, glycerin, or dimethylacetamide gave relatively slow degradation rates at 100 degrees with all projected 25 degrees t 99% values greater than 4.5 years. Intravenous administration of pentobarbital sodium in various anhydrous propylene glycol-based vehicles to rats produced no hemolysis of gross organ damage that would interfere with pathological evaluations. Results of an intraperitoneal sleeptime study indicated that pentobarbital sodium produced consistent hypnotic effect when administered as an aqueous solution or in anhydrous propylene glycol-based vehicles.
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163
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Yamamoto I, Ho IK, Loh HH. Acceleration of pentobarbital metabolism in tolerant mice induced by pentobarbital pellet implantation. Life Sci 1977; 20:1353-62. [PMID: 853867 DOI: 10.1016/0024-3205(77)90361-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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164
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Abstract
A review is presented of published and some unpublished work dealing with aspects of drug clearance from horses. This work includes plasma half-lives and urinary clearance times for specified drugs, as well as a consideration of more general factors likely to influence these values. The review is presented primarily as a guide to the veterinary surgeon in practice, to assist in the drug therapy of horses without contravening the Rules of Racing relating to doping.
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165
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166
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Törrönen R, Alakuijala P, Marselos M. Chelating agents and hepatic drug metabolism in the rat. ARCHIVES INTERNATIONALES DE PHARMACODYNAMIE ET DE THERAPIE 1977; 226:11-20. [PMID: 405937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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167
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168
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Chu CK, Stella VJ, Bruckner JV, Jiang WD. Effects of long-term exposure to environmental levels of polychlorinated biphenyls on pharmacokinetics of pentobarbital in rats. J Pharm Sci 1977; 66:238-41. [PMID: 402468 DOI: 10.1002/jps.2600660227] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The pharmacokinetics of pentobarbital, 30mg/kg iv, were studied in untreated rats and rats pretreated with 1,5, and 25 ppm of polychlorinated biphenyls in food for up to 140 days. Environmental contaminants may contribute to variations in metabolic rates of drugs by causing enzyme induction. The objective of this work was to quantitate the effects of environmental levels of the contaminant and enzyme inducer, a polychlorinated biphenyl, on the pharmacokinetics of pentobarbital, a drug whose primary elimination route is liver metabolism. The pharmacokinetics of pentobarbital in rats could be fit to a biexponential equation of the type Cp = Ae-alpha t+ Be-beta t. After 35 days of pretreatment, only the 25-ppm-treated rats showed any significant acceleration of pentobarbital elimination. At the 70- and 140-day samplings, both the 5- and 25-ppm pretreatments showed significant acceleration of pentobarbital elimination. There were no significant effects on A, alpha, B, and Vd for any pretreatment. The beta-values for the 25-ppm-pretreated rats reached a constant value from the 35-day pretreatment period onward. A calculation of total body clearance suggested that pentobarbital elimination in those rats had approached portal blood flow rate-limited metabolism.
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169
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Pickens R, Cunningham MR, Heston LL, Eckert E, Gustafson LK. Self-administration of sedatives by humans. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1977; 85B:495-502. [PMID: 596285 DOI: 10.1007/978-1-4615-9038-5_31] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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170
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Crane PD, Cornford EM, Braun LD, Oldendorf WH. Brain concentrations of [14C]pentobarbital after intracarotid, intravenous, and intraperitoneal infection. GENERAL PHARMACOLOGY 1977; 8:315-8. [PMID: 604156 DOI: 10.1016/0306-3623(77)90006-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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171
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Tang BK, Inaba T, Kalow W. N-Hydroxylation of pentobarbital in man. DRUG METABOLISM AND DISPOSITION: THE BIOLOGICAL FATE OF CHEMICALS 1977; 5:71-4. [PMID: 13978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
After oral administration of 14C-labeled pentobarbital to healthy subjects, most ot the radioactivity was recovered in urine over a period of 6 days. Only a minute amount (approximately 1%) of unchanged pentobarbital was found in the urine. Four major metabolites were found and isolated. One was 3'-hydroxypentobarbital, which has been previously identified by Maynert. The second could be identified as N-hydroxypentobarbital on the basis of its spectral and chemical properties. The other two metabolites were not identified.
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172
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Nash AH, Bender AE. The effect of dietary sucrose on the metabolism of pentobarbitone [proceedings]. Proc Nutr Soc 1976; 35:132A-133A. [PMID: 1028063 DOI: 10.1079/pns19760062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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173
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Bowery NG, Dray A. Barbiturate reversal of amino acid antagonism produced by convulsant agents. Nature 1976; 264:276-8. [PMID: 187949 DOI: 10.1038/264276a0] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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174
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Liu SJ, Wang RI. Enhanced development of tolerance to pentobarbital by desipramine inhibition of pentobarbital metabolism. Biochem Pharmacol 1976; 25:2211-4. [PMID: 971334 DOI: 10.1016/0006-2952(76)90135-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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175
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de Repentigny L, Hanasono GK, Plaa GL. The influence of acute diazepam pretreatment on the action and disposition of [14C]pentobarbital in rats. Can J Physiol Pharmacol 1976; 54:671-4. [PMID: 990998 DOI: 10.1139/y76-093] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Diazepam (DZP) pretreatment (100mg/kg, ip) of rats 6 h before pentobarbital administration (45 mg/kg, ip) prolonged the barbiturate-induced narcosis. The concentrations of [14C]pentobarbital and total pentobarbital derivatives in blood or brain showed no differences between control and DZP-pretreated animals. The brain and blood concentrations of pentobarbital, when measured at a time corresponding to the respective arousal times from pentobarbital narcosis, were lower in the DZP-pretreated group. These results indicate that acute DZP pretreatment increases the sensitivity of the rat brain to pentobarbital rather than inducing changes in the disposition of the barbiturate.
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