Evaluation of the modulatory influence of black pepper (Piper nigrum, L.) on the hepatic detoxication system

The present paper assesses the modifying potential of black pepper on the hepatic biotransformation system in mice. The modulatory effect was assessed on glutathione S-transferase (GST), cytochrome b5 (cyt. b5), cytochrome P-450 (cyt. P-450), acid-soluble sulfhydryl (-SH) content and malondialdehyde (MDA) level. Swiss albino mice of either sex (eight weeks old) were fed on a diet containing 0.5%, 1% and 2% black pepper (w/w) for 10 and 20 days. The findings revealed a significant and dose-dependent increase in GST and -SH content in the experimental groups except the one maintained on 0.5% black pepper diet for 10 days. Elevated levels of cyt. b5 and cyt. P-450 were also statistically significant and dose-dependent. The level of MDA was lowered in the group fed on 2% black pepper diet for 20 days. Being a potential inducer of detoxication system, the possible chemopreventive role of black pepper in chemical carcinogenesis is suggested.

Effects of arecoline on phase I and phase II drug metabolizing system enzymes, sulfhydryl content and lipid peroxidation in mouse liver

The modifying potential of arecoline alkaloid was studied on hepatic drug metabolizing system enzymes, acid soluble sulfhydryl (-SH) content and microsomal lipid peroxidation. Arecoline was administered intraperitoneally to Swiss albino mice at the dose levels of 10, 20 or 40 mg/kg body wt./day for 10 or 30 days. Significant increase in the levels of glutathione S-transferase (GST), cytochrome b5 (Cyt.b5), cytochrome P-450 (Cyt.P-450) and malondialdehyde (MDA) was observed in the arecoline treated groups. Decreased -SH content was apparent by the administration of 40 mg arecoline for 10 or 30 days. The modulation in biotransformation system enzymes has wide significance in the process of neoplastic development as well as in detecting the further role of biometabolized chemicals.

Modulatory effect of Areca nut on the action of mace (Myristica fragrans, Houtt) on the hepatic detoxification system in mice

The present paper reports the modifying potential of areca nut (Areca catechu), an ingredient of the habitual masticatory betel quid, on the induction of the hepatic detoxification system in mice by mace (the aril of nutmeg, Myristica fragrans) a known chemopreventor of chemically induced carcinogenesis. The modulatory effect of areca nut was assessed by determining the levels of enzymes of the hepatic detoxification system, such as glutathione S-transferase (GST), cytochrome b5 and cytochrome P-450, and the content of acid-soluble sulphhydryl (-SH). Mice were fed either control diet or diet containing 0.25, 0.5 or 1% areca nut for 45 days. During the last 10 days the diet was supplemented with 0.5 or 1% mace. At 0.5 and 1% in the diet, areca nut decreased mace-induced increases in hepatic GST and -SH levels and elevated further increases in the levels of cytochrome b5 and cytochrome P-450.

New esters of heteryl acetic and mercaptoacetic acids. Synthesis and H1-antihistaminic evaluation

Synthesis of esters containing 2 (N,N-dialkylamino) ethanolic and 2-alkoxyethanolic groups with heteroaryl acids was carried out. Three series of such esters: (2-substituted-3,4-dihydro-4-oxo-quniazolin-3-yl) acetates, S-(3-aryl-3,4-dihydro-4-oxo-quinazolin-2-yl) mercaptoacates and S-(1H-benzimidazol-2-yl) mercaptoacetates were synthesized from their respective acids/acid chlorides using appropriate alcohols. Their in vivo H1-antihistaminic potencies were evaluated using isolated guinea pig ileum method. The IC50 values indicate higher potencies of quinazolinonyl mercaptoacetates than the other two series, in general. Presence of an aryl group at position 3, with an electron-releasing substituent appears to enhance the antihistaminic activity. Similarly 2 (N,N-diethylamino) ethyl esters were found to be more active than the other type of esters tested.

Folacin and cyanocobalamin in relation to natural Trypanosoma evansi infection in buffaloes

The haematological values of haemoglobin (Hb), packed cell volume (PCV) and vitamin levels of folacin (folic acid), cyanocobalamin (vitamin B12) of buffaloes, in a surra endemic area of Eastern Haryana, India, were determined. Surra-positive buffaloes had significantly low levels of Hb, PCV, folic acid and vitamin B12. These low levels of folic acid and vitamin B12 may have enhanced the clinical signs of chronic trypanosomiasis, caused by Trypanosoma evansi.

Influence of arecoline on immune system: III. Suppression of B cell-mediated immune response in mice after short-term exposure

Arecoline, a major alkaloid of arecanut was examined to explore its modulatory influence on B cell-mediated immune response in a murine model system. The in vivo and in vitro effects were evaluated at sub-toxic concentrations of arecoline. The number of primary antibody forming cells (AFC) and hemagglutinating and hemolysis antibody titers to Sheep Red Blood Cells (SRBC) were evaluated in male mice. Arecoline exposure for a week invoked dose-dependent effect on primary antibody forming cells to SRBC with a maximum reduction at the dosage of 20 mg/kg bw, a moderate reduction at 10 mg/kg bw and no effect at 5 mg/kg bw dose level. HA and HL antibody titers to SRBC were suppressed markedly at arecoline dosage of 20 mg/kg bw and moderately at a dose of 10 mg/kg bw, given daily for 1, 2 or 3 weeks. The inhibitory effect of arecoline was not dependent on the duration of treatment. Like the primary antibody response, the secondary HA and HL antibody titers were also decreased after arecoline exposure. The administration of arecoline dosages 10 and 20 mg/kg bw daily for 4 days following SRBC immunization also, exerted dose-dependent suppression of primary antibody response. Similarly, when treated after 12 h following immunization, significant reduction in response was observed with arecoline dosage of 20 mg/kg bw. While moderate suppression of antibody response was noticed at the dose level of 10 mg/kg bw, there was no alteration in response at a dosage of 5 mg/kg bw.(ABSTRACT TRUNCATED AT 250 WORDS)

Modulatory influence of sandalwood oil on mouse hepatic glutathione S-transferase activity and acid soluble sulphydryl level

The effect of the oil from the wood of Santalum album on glutathione S-transferase (GST) activity and acid soluble sulphydryl (SH) levels in the liver of adult male Swiss albino mice was investigated. Oral feeding by gavage to mice each day with 5 and 15 microliters sandalwood oil for 10 and 20 days exhibited an increase in GST activity in time- and dose-responsive manners. Feeding a dose of 5 microliters sandalwood oil for 10 and 20 days caused, respectively, a 1.80-fold (P < 0.001) and 1.93-fold (P < 0.001) increase in GST enzyme activity, while feeding a dose of 15 microliters of the oil per day for 10 and 20 days induced, respectively, 4.73-fold (P < 0.001) and 6.10-fold (P < 0.001) increases in the enzyme's activity. In addition, there were 1.59-fold (P < 0.001) and 1.57 (P < 0.001) increases in acid-soluble SH levels in the hepatic tissue of the mice following feeding of the oil at the dose levels of 5 and 15 microliters for 10 days. Furthermore, mice fed on a diet containing 1% 2(3)-butyl-4-hydroxyanisole (positive control) also showed an increase in hepatic GST activity and SH levels. Enhancement of GST activity and acid-soluble SH levels are suggestive of a possible chemopreventive action of sandalwood oil on carcinogenesis through a blocking mechanism.

Evaluation of the modulatory influence of food additive-garam masala on hepatic detoxication system

Potential chemopreventive role of an Indian food additive-garam masala has been assessed through its impact on the hepatic levels of detoxication enzymes like glutathione S-transferase (GST), cytochrome b5 (cyt. b5) and cytochrome P-450 (cyt. P-450), and acid soluble sulfhydryl (-SH) content in 8-9 weeks old Swiss albino mice of either sex fed on the 0.5%, 1.0% and 1.5% (w/w) garam masala in the diet for 10 days. The data from this short term study revealed the significant but dose-independent alteration in the levels of detoxication system enzymes. The results suggest the possible chemopreventive potency of this widely used food additive by being a bifunctional inducer of detoxication system.

Modulatory influence of oral contraceptive pills Ovral and Noracycline on 3-methylcholanthrene-induced carcinogenesis in the uterine cervix of mouse

The present study reports the modulatory influences of combined oral contraceptive formulations, Ovral (0.05 mg ethinylestradiol plus 0.5 mg norgestrel per pill) and Noracycline (0.05 mg ethinylestradiol plus 0.1 mg lynestrenol per pill), on methylcholanthrene (MCA)-induced carcinogenesis in the uterine cervix of Swiss albino mouse. Placement of cotton thread impregnated with beeswax containing approximately 300 micrograms of MCA yielded cervical tumors in 0.0%, 8.6% and 26% animals, respectively, in 30, 60 and 90 days. Concomitant treatments with doses D1 (1/2000th of a pill), D2 (1/200th of a pill) and D3 (1/20th of a pill) of Ovral yielded cervical tumors in 0.0%, 0.0% and 4.5% mice at 30 days, 0.0%, 6.2% and 10% mice at 60 days and in 3.3% (P less than 0.05), 3.4% (P less than 0.05) and 47% mice at 90 days, respectively. Likewise, concomitant treatments with doses D1 (1/2000th of a pill), D2 (1/200th of a pill) and D3 (1/20th of a pill) of Noracycline yielded cervical tumors in 0.0%, 0.0%, 16.6% mice at 30 days, 4%, 3.7% and 54% (P less than 0.05) mice at 60 days and 3.2% (P less than 0.05), 20% and 63% (P less than 0.05) of mice at 90 days, respectively. Both Ovral and Noracycline displayed biphasic action on MCA-induced cervical carcinogenesis in mice. At lower dose levels (D1 and D2), they were inhibitory while at the higher dose level (D3) they were augmentatory in their actions. Both pills also significantly enhanced the incidence of cervical hyperplasia.

Diosgenin--a growth stimulator of mammary gland of ovariectomized mouse

Estrogenic action of diosgenin on the mammary epithelium of ovariectomized (OVX) mouse has been reported. Diosgenin when administered (sc) at the dose levels of 20 and 40 mg/kg body weight for a period of 15 days stimulated the growth of mammary epithelium. This was indicated by the increase in DNA content, increase in number of ducts and appearance of terminal endbuds. There was a significant increase in the mammary development scores in the presence of diosgenin. Concomitant treatment of estrogen and diosgenin showed augmentation of estrogenic effect of diosgenin especially at the higher dose level (40 mg/kg body wt). Diosgenin showed a lack of progesterogenic action as was apparent from the absence of alveolar development even in the presence of exogenous estrogen.

Caffeine, theophylline, theobromine, and developmental growth of the mouse mammary gland

The purpose of this study was to determine the comparative activities of three methylxanthines, i.e., 1,3,7-trimethylxanthine (caffeine), 1,3-dimethylxanthine (theophylline), and 3,7-dimethylxanthine (theobromine) on developmental growth of the mammary gland in ovarian-hormone treated, mature nulliparous female Balb/c mice. When caffeine or theophylline was administered daily (via drinking water, 500 mg/L) for 30 days to 17 beta-estradiol/progesterone-treated intact or ovariectomized mice, a significant (p less than 0.05) enhancement of hormone-induced mammary gland lobulo-alveolar differentiation was observed. Caffeine or theophylline thus accelerated and/or intensified mammae lobulo-alveolar differentiation induced by the ovarian steroids. In contrast, theobromine (500 mg/L drinking water) did not significantly modify this developmental process. The stimulatory effect of caffeine and theophylline on mammae development was comparable quantitatively. In an effort to determine whether or not the stimulatory effect of caffeine or theophylline was directly on the mammary gland, small slow-release Elvax-40P pellets containing these methylxanthines were implanted directly into the mammary gland of mice concurrently treated with estrogen and progesterone. No significant stimulatory effect of caffeine or theophylline (or theobromine) was observed. Furthermore, the addition of methylxanthines (caffeine, 100 microM) to the culture media of whole mouse mammary glands (organ cultures) did not enhance lobulo-alveolar differentiation induced by mammotrophic hormones. Thus, while a consistent significant stimulatory effect of caffeine and theophylline on mammary lobulo/alveolar differentiation was observed when the methylxanthines were consumed orally (drinking water), no direct effect of these methylxanthines, when placed directly into the mammary gland or in culture media, on mammae development was observed. These data demonstrate that certain methylxanthines (e.g., caffeine and theophylline) but not others (e.g., theobromine) can significantly enhance mammotrophic hormone-induced mammary lobulo-alveolar differentiation in female Balb/c mice, an effect that appears not to be manifested via a direct action of the methylxanthines on the mammary gland.

Promoting action of cashew nut shell oil in DMBA-initiated mouse skin tumour model system

The commercially available oil derived from the shell of cashew nut (Anacardium occidentale) was tested for its potency in promoting the DMBA-initiated cells into papillomas in a murine two-stage skin tumorigenesis model system. Male Swiss albino mice (9-10-weeks-old) were assorted into different groups and treated topically with single sub-carcinogenic doses of DMBA (50 micrograms in 0.1 ml acetone) followed by application of 1% and 2% shell oil in acetone three times a week. Animals were sacrificed after 20 weeks from the commencement of the experiment. The results imply a weak tumour promoting effect of cashew nut shell oil as the mean tumour incidences were found to be 1.1 and 2.5 in 1% and 2% oil treatment groups, respectively, while the corresponding figure vas 6.6 in the positive control group (DMBA and 1% croton oil in acetone). Few speculative mechanisms for the observed effect of cashew nut shell oil on initiated skin are discussed.

Inhibition of key enzymes of carbohydrate metabolism in regenerating mouse liver by ascorbic acid

The effect of ascorbic acid on the key enzymes of carbohydrate metabolism e.g. hexokinases, phosphofructokinase, pyruvate kinase, lactate dehydrogenase, glucose-6-phosphate dehydrogenase and malic enzyme was determined in regenerating mouse liver. All the enzymes showed a significant increase in the activity during regeneration. Ascorbic acid reduced the activities of the enzymes in regenerating liver. A decrease in liver weight in ascorbic acid treated animals may be correlated with its effect on these enzymes as glycolytic pathway is the main source of energy required by the dividing cells.

Modulatory influence of injectable contraceptive steroid medroxyprogesterone acetate on methylcholanthrene-induced carcinogenesis in the uterine cervix of mouse

Methylcholanthrene (approximately 300 micrograms) plus beeswax-impregnated thread, when placed inside the canal of the uterine cervix of virgin female adult mice for 30, 60 and 90 days produced cervical tumors in 0.0, 10 and 30% of mice, respectively. Employing this experimental cervical carcinogenesis model system, the present study evaluated the modulatory influence of medroxyprogesterone acetate (MPA) on the incidences of precancerous and cancerous lesions in the cervical epithelium as well as on phase I and phase II drug metabolizing enzymes and acid soluble sulfhydryl level in the liver. Intramuscular administration of MPA (50 micrograms every 5th day) to the carcinogen-thread inserted mice for 30, 60 and 90 days produced cervical tumors respectively in 0.0, 13.3 and 60.5% (P less than 0.05) of mice. A significant increase (P less than 0.05) in hyperplasia was also observed in the present study. A significant decrease in cytochrome b5 was found after 30 days.

Chemopreventive action of selenium on methylcholanthrene-induced carcinogenesis in the uterine cervix of mouse

The placement of cotton thread impregnated with beeswax containing methylcholanthrene (MCA, approximately 600 micrograms) inside the canal of the uterine cervix of virgin, adult mice results in the emergence of precancerous and cancerous lesions in the cervical epithelium. Employing this experimental carcinogenesis model system, the present study evaluates the chemopreventive action of selenium on the incidences of precancerous and cancerous lesions in the cervical epithelium. When selenium was administered through drinking water at the dose level of 1 ppm for 1 week before and 12 weeks following carcinogen thread insertion, the cervical carcinoma incidence, as compared to that in control mice (72%), was 37%. This decline in the incidence of carcinoma was significant (p less than 0.05). The incidences of hyperplasia and dysplasia show a decreasing trend with selenium treatment in MCA-thread-inserted animals.

Neonatal modulation of hepatic acid soluble sulfhydryls and xenobiotic metabolizing enzymes in suckling mice exposed translactationally to butylated hydroxyanisole

The present study examines the effect of butylated hydroxyanisole (BHA) exposure through mother's milk on some of the hepatic xenobiotic metabolizing enzymes in the F1 offspring. Lactating Swiss albino mice received either a 0.5 or 1% BHA diet during the lactation period. The acid-soluble sulfhydryl content and activities of glutathione S-transferase and glutathione reductase increased significantly (p < 0.01) whereas the activity of glutathione peroxidase decreased significantly (p < 0.01) in the liver of pups exposed to BHA via milk. The hepatic content of cytochrome b5 increased (p < 0.01) while that of cytochrome P-450 decreased (p < 0.01) in the pups of dams which received a 1% BHA diet during lactation.

Effects of oral contraceptive pills on drug metabolizing enzymes and acid soluble sulfhydryl level in mouse liver

The present paper reports the modulatory influence of two widely used combined oral contraceptive pills "OVRAL" and "NORACYCLINE" on hepatic phase I and II drug metabolizing enzymes and acid soluble sulfhydryl group of the mouse. Three different doses of the pills were used in this study i.e. D1 (1/2000th of a pill), D2 (1/200th of a pill) and D3 (1/20th of a pill). The sulfhydryl group increased significantly with the D1 and D2 dose of Ovral and the D2 dose of Noracycline. Dose D2 of both pills decreased cyt.P450 and cyt.b5 contents. D3 of Noracycline, however increased both the cytochrome levels. Dose D3 of Ovral and all three doses of Noracycline reduced the glutathione S-transferase activity.

Caffeine inhibits development of benign mammary gland tumors in carcinogen-treated female Sprague-Dawley rats

The purpose of this study was to assess the influence of caffeine on the incidence of benign mammary tumors in carcinogen (DMBA) treated female Sprague-Dawley rats. Four different animal models were used in these studies, i.e., the administration of DMBA to: [1] 55 day old virgin rats; [2] 53 day old ovariectomized, estrogen treated virgin rats; [3] 135 day old virgin rats and [4] 135 day old parous rats. A high incidence of benign mammary fibroadenomas was observed in each of the four animal models. In addition, in the estrogen treated ovariectomized animals, a high incidence of secretory mammary gland cysts was observed. Caffeine (500 mg/L drinking water) was administered daily throughout the study commencing 3-31 days after carcinogen treatment. Caffeine treatment significantly (P less than 0.05 to P less than 0.001) reduced the incidence of benign mammary fibroadenomas in the 55 day old virgin rat model (P less than 0.01), in the 53 day old estrogen treated ovariectomized virgin rat model (P less than 0.05 to P less than 0.001) and in the 135 day old virgin rat model (P less than 0.05). The number of benign mammary fibroadenomas was reduced by caffeine in the 135 day old parous rat model but this reduction was not significant (P less than 0.10). In addition, in the estrogen treated ovariectomized virgin rat model, caffeine significantly (P less than 0.05 to P less than 0.001) reduced the incidence of mammary gland cysts. Caffeine treatment either increased or had no significant effect on body weight gains, depending upon the animal model.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of 17 beta-estradiol and ovariectomy on enzymes of carbohydrate metabolism in regenerating mouse liver

Effect of exogenous 17 beta-estradiol and ovariectomy was determined on the activities of some enzymes of carbohydrate metabolism in regenerating mouse liver. 17 beta-estradiol increased liver weight and the activities of these enzymes when given after partial hepatectomy whereas ovariectomy, performed 2 weeks prior to hepatectomy, reduced the activities significantly. Estradiol administration to ovariectomized-partially hepatectomized animals restored the activities of glycolytic enzymes but not of G6P-DH and malic enzyme. This indicates that estradiol acts as a stimulator of growth of proliferating liver as it does in target tissue.

Chemopreventive action of mace (Myristica fragrans, Houtt) on methylcholanthrene-induced carcinogenesis in the uterine cervix in mice

The present paper reports the chemopreventive action of mace (aril covering the testa of the seed of Myristica fragrans) on 3-methylcholanthrene (MCA)-induced carcinogenesis in the uterine cervix of virgin, young adult, Swiss albino mice. Placement of cotton-thread impregnated with beeswax containing MCA (approximately 600 micrograms) inside the canal of the uterine cervix results in the appearance of precancerous and cancerous lesions in the cervical epithelium. In this experiment using the cervical carcinogenesis model system, if mace was administered orally at the dose level of 10 mg/mouse per day for 7 days before and 90 days following carcinogen thread insertion, the cervical carcinoma incidence, as compared with that of the control (73.9%), was 21.4%. This decline in the incidence of carcinoma was highly significant (P less than 0.001). The incidence of precancerous lesions did not display any definite association with different treatments.

Influence of arecoline on immune system: II. Suppression of thymus-dependent immune responses and parameter of non-specific resistance after short-term exposure

Arecoline, a major alkaloid of arecanut was screened to explore its modulatory influence on cell-mediated immune response in a murine model system. The in vivo and in vitro effects were evaluated at subtoxic concentrations of arecoline. Delayed type hypersensitivity (DTH) reactions to sheep red blood cells (SRBC) were evaluated in male mice. When treated subcutaneously with 20 mg/kg bw (1/5 of LD50) dose of arecoline for 1, 2 or 3 weeks, the DTH reactions were significantly suppressed. At arecoline concentration of 10 mg/kg bw, there was a moderate reduction in DTH response, while no appreciable change was observed at a dosage of 5 mg/kg bw. The effects were not dependent on the duration of treatment. In contrast, treating with arecoline continuously for 4 days following SRBC immunization showed significant suppression in DTH reactions at both 10 and 20 mg/kg bw doses. When treated after 12 h following immunization with 20 mg/kg bw arecoline, significant reduction in DTH reactions were seen. While moderate reduction in response was observed with arecoline dosage of 10 mg/kg bw, there was no alteration in response at the dose level of 5mg/kg bw. Recovery experiments in mice revealed that arecoline mediated effects are of a reversible nature. Arecoline treatment did not appreciably alter the host resistance to endotoxin shock. In vitro experiments revealed both dose-dependent and time-dependent cytotoxic effects of arecoline when spleen cells were incubated with varying concentrations of arecoline. Concomitant exposure of arecoline at concentrations of 10(-6) - 10(-4) M with con A, markedly suppressed both 3H-thymidine incorporation and interleukin-2 production of splenic cells. In contrast, concomitant exposure of arecoline with IL-2 did not alter 3H-thymidine incorporation in the IL-2 dependent cytolytic T-lymphocyte line (CTLL), except at the concentration of 10(-4) M arecoline. From these studies it is concluded that the dose-dependent suppressive effects of arecoline on DTH response to SRBC and on certain in vitro lymphocyte functions are more clear than the host resistance to endotoxin shock.

Chemopreventive action of mace (Myristica fragrans, Houtt) on DMBA-induced papillomagenesis in the skin of mice

The present paper reports the chemopreventive property of mace (aril covering the seed of Myristica fragrans) on DMBA-induced papillomagenesis in the skin of male Swiss albino mice. When a single topical application of DMBA (150 micrograms in 100 microliters of acetone) was followed, 2 weeks later, by repeated applications of croton oil (1% in acetone, three times/week) skin papillomas appeared in 100% animals and the average tumors per tumor-bearing animal was 5.67. On the other hand, when animals receiving similar treatments were put on a diet containing 1% mace during the periinitiational phase of tumorigenesis, the skin papilloma incidence was reduced to 50% and the average tumor per tumor-bearing mouse was only 1.75. This decline in papilloma was significant (P less than 0.05).

Chemoprevention of 7,12-dimethylbenz[a]anthracene-induced mammary carcinogenesis in rat by the combined actions of selenium, magnesium, ascorbic acid and retinyl acetate

The chemopreventive actions of sodium selenite (SS), magnesium chloride (MC), ascorbic acid (AA) and retinyl acetate (RA), given singly or in combinations, on mammary carcinogenesis induced by 30 mg of 7,12-dimethylbenz[a]anthracene (DMBA) in female adult rats were evaluated. Administration of modulators was carried out from the age of 40 +/- 3 days to 240 +/- 3 days. When DMBA alone was given 100% of the rats developed mammary tumors. When modulators were given singly the tumor incidences were reduced to 51.77% (SS), 46.4% (MC), 57.1% (AA) and 48.1% (RA). When the modulators were given in combination of twos, the tumor incidences were further reduced to 29.5% (SS + MC), 31% (SS + AA), 29.6% (SS + RA), 25.9% (MC + AA), 31.8% (MC + RA) and 34.6% (AA + RA). Administration of modulators in combinations of threes resulted in still further reduction of tumor incidences to 22.2% (SS + MC + AA), 19.2% (SS + MC + RA), 16% (MC + AA + RA) and 23.1% (AA + RA + SS). When all four modulators were given concurrently the tumor incidence was only 12%. Further, the number of tumors per tumor-bearing animal declined with the increase in the number of agents used in combination for modulation.

Modulatory influences of tamoxifen, tocopherol, retinyl acetate, aminoglutethimide, ergocryptine and selenium on DMBA-induced initiation of mammary carcinogenesis in rats

Present study evaluates the chemopreventive actions of tamoxifen (10 mg/kg), retinyl acetate (50 mg/kg), tocopherol (200 mg/kg), aminoglutethimide (1 mg/kg), ergocryptine (5 mg/kg), and sodium selenite (1 mg/kg) when given singly/in combinations on the initiation of mammary carcinogenesis induced by 20 mg of DMBA in virgin female rats. DMBA was given when rats were 50 days old and the modulators were given in diet 10 days before and 10 days after carcinogen treatment and experiments were terminated 6 months later. DMBA alone yielded tumors in 62% rats. When modulators were given singly and in combinations of two, tumor incidences were not altered significantly. The range of tumor incidences was between 30% and 13% when the agents were given in combinations of 3, 4 and 5. Finally when all 6 modulators were given together the tumor incidence dropped down to 8.3%.