Neurobehavioral effects in offspring of rats exposed to prenatal hyperthermia

Poster Session 2J. Carcinogenesis

68

EFFECTSIN OFFSPRING OF IP21-2451NEUROBEHAVIORAL RATS EXPOSED TO PRENATAL HYPERTHERMIA

Keywords: bioreductive enzymes; human cell lines; solid tumors; xenografts; western blot; bioreductive agents

Germ~in Chamorro *, Patricia Vistrain, Silvia Salazar, Marfa Salazar. I

National Polytechnic Institute, National School of Biological Sciences, Department of Toxicology, M~xico D.E, M~xico

BIOREDUCTIVE ENZYMES IN LUNG AND BREAST IP2J-2471 TUMORS

Hyperthermia causes several congenital abnormalities in a number of domestic and laboratory species of mammals, including defects on the central nervous system [1]. The purpose of this study was to investigate the effects of prenatal hyperthermia exposure on developmental and behavioral repertoire of the offspring, through 12 weeks of age. Pregnant Wistar rats were exposed to 37 (control), 40, 41 or 42°C, for 15 minutes once dally, by partial immersion in a water bath, from gestational day 15 to 21. Dams were allowed to deliver normally. Litters were culled to eight pups at birth and fostered to normal lactating dams. No maternal or reproductive toxicity was detected. Surface righting, negative geotaxis, wire hanging maneuver and sexual behavior revealed no differences between hyperthermia exposed offspring and control groups. However, pre-weaning body weights were decreased in both, females and males. Physical landmarks such as pinna unfolding, tooth eruption and eye opening, were delayed in animals of both sexes. Clift avoidance and auditory startle developed also latter. Frequency and duration of entrances in an hole-board exploration test were significantly decreased. These results are consistent with the suggestion that hyperthermia is a potential behavioral teratogen.

Ana Marfn * i, Adela L6pez de Ceraln i, Alexander D. Lewis 4, Elisabeth Hamilton s, Miguel Idoate 2, Martinez Pefiuela; 3, Jos6 Bello i. 1 Univ. de Navarra, Dpto de Bromatologfa y

[1] Edwards, MJ., Teratogen Carcinogen Mutagen, 6, 563-582, 1986.

Keywords: prenatal hyperthermia; neurobehavioral effects; rats

P2J. Carcinogenesis BIOREDUCTIVE ENZYMES IN TUMOR CELL LINES IP2J-246 1 AND TUMOR MODELS I i

Aria Marin * i, Adela L6pez de Cer~iin 1, Elisabeth Hamilton 2, Alexander D. Lewis 3, Jos6 Bello i. i Universidad de Navarra,

Departamento de Bromatolog(a, Tecnolog(a de los Alimentos y Toxicologfa, CIFA, Pamplona, Spain; 2 ZENECA Pharmaceuticals, United Kingdom; 3 University of Glasgow, United Kingdom The level of expression of the various bioreductive enzymes which catalize the activation and detoxication of bioreductive antitumor agents has emerged as a new selective antitumor strategy. We examined the level of expression of DT-diaphorase (DTD), cyt. P450 reductase, cyt. b5 reductase and alcohol dehydrogenase (ADH), within a panel of both animal and human tumor cell lines, and in some animal solid tumors and xenografts. Enzyme levels were analysed by measuring the enzyme activity or by western blot analysis or by both techniques. Our data indicated that both DTD protein expression and enzyme activity varied between tumour cell lines from different origins and also within cell lines from the same tissue although interestingly, the levels tended to be the same when they shared the same hystologic type. In five human breast lines the expression of DTD varied from almost undetectable, to a very high enzyme activity, 1261.0 + 50.3 nmol/min/mg protein. Two of these cell lines were carcinomas and presented the higher values. The other three were adenocarcinomas and with the exception of MDAMB-468, which did not have activity or protein, they presented about twofold less activity than the carcinomas. Compared to DTD, bs reductase and P450 reductase were low in all the samples studied (5.5-209.3 and 4.3--61.2 nmol/mirdmg, respectively). ADH was expressed in almost all the samples assayed. This data provides a valuable data base to search for correlations with the antitumor potencies of known and novel compounds. Acknowledgements: To ZENECA Farma for finantial support.

i

Toxicologla, CIFA, Pamplona, Spain; 2 Univ. de Navarra, CUN, Pamplona, Spain; 3 Hosp. de Navarra, Pamplona, Spain; 4 Universidad de Glasgow, United Kingdom; 5 ZENECA Pharmaceuticals, United Kingdom The level of expression of enzymes which catalize the activation or protection metabolic pathways of the antitumor agents known as bioreductive drugs is emerging as a very important feature in the development of these compounds. We examined the level of expression of various reducing enzymes including DT-diaphorase (DTD), carbonyl reductase (CR), and alcohol dehydrogenase (ADH), within breast and lung paired normal and tumor samples. Enzyme levels in these samples were analyzed by measuring the enzyme activity, or by western blot analysis or by both techniques. DTD was induced in the tumor tissue of the majority of the patients. DTD variation in lung tumors was bigger than in breast tumors, from 0.9 to 966 and from 5.4 to 267 nmol/min/mg, respectively. The basal activity (nmol/mirdmg) in normal tissues was between 0--40 for lung and between 2---44 for breast. Expression of DTD measured by western blot analysis showed significant correlation with the activity measured. CR was also induced in breast and lung tumors, showing a similar increase in both tissues (up to 250 nmol/min/mg in both). On the contrary, the expression of ADH was higher in the normal tissue than in the tumor tissue for most of the patients, decreasing the possible interest of this enzyme in the activating pathways of the bioreductive drugs. The results emphasize the importance of determining the actual activities of bioreductive enzymes, particularly the biopsies of patients prior to treatment as an aid of clinical decision making. Acknowledgements: To ZENECA Farma for finantial support.

Keywords: DT-diaphorase; carbonyl reductase; alcohol dehydrogenase; lung tumors; breast tumors; bioreductive drugs I

OF PYRIDINE ON RABBIT LIVER AND IP2J-2481 EFFECTS LUNG MICROSOMAL N-NITROSODIMETNYLAMINE i

N-DEMETHYLASE AND ANILINE ~HYDROXYLASE ENZYME ACTIVITIES

Orhan Adali *, A. Mine Gentler Ozkan, Emel Arinq. Middle East

Technical University, Joint Graduate Program in Biochemistry, Ankara, Turkey This study was undertaken to investigate, in vivo effects of pyridine treatment on microsomal cytochrome P450 dependent N-nitrosodimethylamine (NDMA) N-demethylase and aniline 4hydroxylase activities and P450 levels in rabbit liver and lung. New Zealand white rabbits were injected 3 times intraperitoneally with pyridine at a dose of 250 mg/kg body weight on day 1, 5 and 8. Liver and lung microsomes of control and pyridine treated rabbits were prepared [1] and used for determination of cytonhrome P450 contents and microsomal drug metabolizing enzyme activities. Results obtained in this study showed that liver and lung microsomal NDMA N-demethylase activity, associated with P4501E1, was increased 6.9- and 5.15-fold, respectively by pyridine treatment. Aniline 4-hyroxylase activity was enhanced by pyridine treatment in liver about 5.8 fold but no change was observed in the activity of enzyme of lung microsomes. Pyridine treatment also elevated P450 contents of liver and lung by 2.04- and 1.4-fold, respectively. Induc-