Whole-body autoradiography

Bergman K. 1983a. Application and results of the whole-body autoradiography in distribution studies of organic solvents. CRC Crit Rev Toxicol 12 59-118. 

Burreau S, Broman D, Om U (2000) Tissue distribution of 2, 2,4,4-tetrabromo[14 Cjdiphenyl ether([ 14 C]-PBDE 47) in pike (Esox lucius) after dietary exposure a time series study using whole body autoradiography. Chemosphere 40 977-985... 

Distribution studies by whole-body autoradiography in rats and monkeys revealed accumulation of radiolabel in the liver, kidney, lung, adrenal cortex and stomach. In fetuses exposed in utero, only the eye lens accumulated radiolabel at a higher concentration than that observed in maternal blood (Sandberg and Slanina 1980). 

Balk, L., J. Meijer, J.W. DePierre, and L.E. Appelgren. 1984. The uptake and distribution of (3H) benzo[a]pyrene in the northern pike (Esox lucius). Examination by whole-body autoradiography and scintillation counting. Toxicol. Appl. Pharmacol. 74 430-449. 

The most comprehensive technique currently available for the initial survey of the distribution of a drug is that of whole body autoradiography. The species of animals used include mice, rats, hamsters, monkeys, pigs, dogs, and ferrets. The most widely used animal has been the mouse, which has the advantages of requiring less isotope and being easier to section. 

Reports are published on the metabolism of methoprene by plants (25), aquatic microorganisms (26), soil microbes (27), house flies and mosquitoes in vivo (28), resistant house flies in vivo and in vitro (29), a steer (30), a lactating cow (31), chickens (32), and bluegill fish (33). In addition, radioactive material balance studies have been published for a guinea pig, steer, and cow (34), chickens (35), and rats (36, 37), including whole-body autoradiography in rats (37). 

After whole-body autoradiography to study the distribution of " C-labeled chloroform in mice, most of the radioactivity was found in fat immediately after exposure, while the concentration of radioactivity in the liver increased during the postanesthetic period, most likely due to covalent binding to lipid and protein in the liver (Cohen and Hood 1969). Partition coefilcients (tissue/air) for mice and rats were 21.3 and 20.8 for blood 19.1 and 21.1 for liver 11 and 11 for kidney and 242 and 203 for fat, respectively (Corley et al. 1990). Arterial levels of chloroform in mongrel dogs reached 0.35-0.40 mg/mL by the time animals were in deep anesthesia (Chenoweth et al. 1962). Chloroform concentrations in the inhaled stream were not measured, however. After 2.5 hours of deep anesthesia, there were 392 mg/kg chloroform in brain tissue, 1,305 mg/kg in adrenals, 2,820 mg/kg in omental fat, and 290 mg/kg in the liver. 

Bergman K. 1979. Whole-body autoradiography and allied tracer techniques in distribution and elimination studies of some organic solvents. Benzene, toluene, xylene, styrene, methylene chloride, chloroform, carbon tetrachloride and trichloroethylene. Scand J Work Environ Health 5(Suppl 1) 263. 

Whole-body autoradiography of male Sprague-Dawley rats given intravenous injections (2.7 mg/kg bw) of 7V-nitroso[ C]diethanolamine showed an even distribution in most tissues except for tissue-bound radioactivity that was localized in the liver and the nasal olfactory mucosa. A lower level of labelling in the central nervous system probably indicated that 7V-nitrosodiethanolamine penetrated the blood-brain barrier poorly, while higher labelling in the kidney and urinary bladder may reflect elimination of 7V-nitroso[ C]diethanolamine in urine (Lofbeig Tjalve, 1985). 

The amount of nonmetabolized intact Rgj and Rb2 absorbed by the gastrointestinal tract of the rat is about 1.9 and 0.1% of the doses, respectively.28 With a whole-body autoradiography, Strombom et al.29 (Figure 16.29) have been able to demonstrate in rats the absorption and distribution of the radioactively labeled ginsenoside Rgj and its metabolites after per oral administration of a radioactively labeled ginsenoside Rgj isolated from the G115 extract. 

Whole-body autoradiography of ginsenoside Rgj in mice after oral administration. 

J. Stombom et al., Studies on absorption and distribution of ginsenoside Rgj by whole-body autoradiography and chromatography, Acta Pharm. Suec., 22, 113, 1985. 

Distribution addresses the transfer of the drug compound from the site of administration to the systemic circulation and then to bodily tissues. Both in vitro and in vivo studies are informative here. In vitro studies, for example, examine plasma protein binding. In vivo studies use whole body autoradiography that can display visually how much drug has reached different parts of the body. Transfer of the drug compound in milk to an infant and across the placenta is also studied. 

Hansson, E. and Jacobsson, S.-O. 1966. Uptake of [75Se]selenomethionine in the tissues of the mouse studied by whole-body autoradiography. Biochim. Biophys. Acta 115, 285-293. 

A new series of amide derivatives 293-300 for diagnosis and therapy of disseminated malignant melanoma has been labelled437 139 with iodine-125 exchange between iodoaryl amides and Na125I. These have been used for injection in whole-body autoradiography... 

The radioactivity measured in the kidneys of the rats fed on the early and advanced Maillard casein was higher than in the liver and in the muscle due to a certain retention of the Maillard products, which can be observed in the whole body autoradiography (see Figure 2). 

Figure 2. Whole-body autoradiographies of rats, 24 h after oral ingestion of derivatives of U-14C-i.-lysine lysinoalanine, e-deoxyfructosyllysine, e-formyl-lysine, e-(y-glutamyl)lysine, and a-formyllysine.

Whole-Body Autoradiography. Whole-body autoradiography performed 8 h after intravenous injection of e-deoxyfructosyl-U-14C-lysine shows that the radioactivity is localized in the bladder and in the kidneys since the excretion is not complete, and a little in the pancreas (41). Twenty-four h after oral ingestion, the radioactivity is localized mainly in the large intestine and a little in the cortex of the kidneys, giving the same pattern as 14C-lysinoalanine (see Figure 2). 

Metabolic Transit of 14C-Lysinoalanine in Other Species. In mice and in hamsters, the metabolic transit of lysinoalanine is not very different from that of rats except in the composition of some urinary catabolites (113) and the level of the radioactivity remaining in the kidneys (see Table VIII). In quails the feces contained small amounts of lysinoalanine (6-15%) and only two important catabolites. The urines of mice and hamsters contained two catabolites less than those of rats (see Figure 5), and although mice and hamsters do not develop nephrocytomegaly, they presented the same kind of retention of radioactivity in the kidney cells as rats. This retention in the medular part of the kidneys is well observed on the whole-body autoradiographies of Figure 2 however, in mice and hamsters, this retention is quantitatively less important than in rats (see Table VIII). 

We are grateful to D. Salter of the National Institute for Research in Dairying, Shinfield, Reading, England for the labelling of 3H-lysine casein and R. Jost for its purification. Many thanks to I. Bracco for the whole-body autoradiographies and R. F. Hurrell for his advice and the correction of the manuscript. 

In whole-body autoradiography studies in mice, the radiolabel originating from uC-labeled omeprazole was found to be confined to the gastric mucosa (Fig. 2.6). With a similar technique, and using both fight and electron microscopic evaluation, omeprazole was found to label only the tubulovesicles and secretory membranes of the parietal cell, which contain the H+, K+-ATPase [3]. Electrophoretic analyses of the proteins from such membranes, purified after systemic administration of... 

The data are finally drawn together for detailed discussion and evaluation with special attention to known results from other radiokinetic studies such as the mass balance study and the obtained fecal elimination or the quantitative whole body autoradiography. 

Instead of the described procedure of a common quantitative distribution study, the placental transfer can be investigated nicely also by quantitative whole body autoradiography (see the section on autoradiography and for instance Endo et al. (1992) or Suwelack et al. (1985)). The quantitative whole body autoradiography was extended also for the use of pregnant rabbits (Herman 1998). 

Distribution studies with radiolabeled test substances in animals are an important part of the drag development process. Traditional routine methods used for these studies are quantitative tissue distribution studies (QTD) and alternatively whole-body autoradiography (WBA) with detection of the radioactivity in whole-body sections on X-ray film (John R. J. Baker 1989). WBA is a qualitative detection method with a very high local resolution which includes all organs an many small substructures. 

Quantitative Whole-Body Autoradiography (QWBA) is based on the RLG technique and the use of standards obtained from dilution series containing known concentrations of radioactivity. Isotopes used in QWBA are mainly 14C and 3H. These standards were cut together with the whole-body sections to ensure an identical thickness and used for the internal calibration. The information of the calibration curve allows the determination of the concentrations in the organs and tissues of interest which can be derived from the measured area and the section thickness. 

To save animals and time, the quantitative tissue distribution study is more and more replaced by the quantitative whole-body autoradiography. 

Using radiolabeled drug candidate, perform tissue distribution, with whole body autoradiography, in rodents after single-dose and multiple-dose (if appropriate) administration. 

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