Sage Journals: Discover world-class research

Abstract

Acrylamide is oxidized by cytochrome P450 2E1 (CYP2E1) to its epoxide form, glycidamide, which is believed to be responsible for the mutagenic and carcinogenic activities. This study was carried out to investigate the early changes that may be related to the carcinogenic activity of acrylamide in thyroid, adrenal glands and testis in male rats. Forty adult Sprague Dawley male rats were divided equally into four groups, rats of Group I served as control, and rats of Groups II, III and IV were treated orally with acrylamide with doses 5, 10, 15 mg/kg/day body weight for 8 weeks. The results indicated that the plasma carcino embryonic antigen (CEA) and malondialdehyde (MDA) levels are higher, but free and total testosterone, triiodothyronine (T₃) and thyroxine, or 3,5,3′,5′-tetraiodothyronine (T₄) and corticosterone levels are lower in rats treated with acrylamide than that in control rats. This study provides evidence of endocrine disturbance to the testis, thyroid and adrenal glands, which are also the organs in which acrylamide has been shown to cause tumors in experimental animals.

Keywords

acrylamide glycidamide total antioxidant corticosterone testosterone

Introduction

Acrylamide does not occur naturally. It was found in many human foodstuffs which include fried, deep-fried, oven-baked foods, chips, bread, biscuits, crackers and breakfast cereals.^1–3 The major pathway in the formation of acrylamide in food cooked at high temperature involves the Maillard browning reaction between reducing sugars and asparagine, an amino acid found in potatoes and cereals.^4–6 Acrylamide has been found to cross the placenta in humans and it has been found in human breast milk. Thus, dietary acrylamide exposure is likely begun in utero and continue throughout the life span.⁷

Acrylamide is chemically reactive toward nucleophiles, including amino and thiol groups in amino acids and proteins, by Michael additions to the carbon–carbon double bond. This kind of reaction generates adducts of acrylamide with the N-terminal valine residue in hemoglobin.⁸

Acrylamide is weakly reactive with DNA in vitro, generating adducts with the ring nitrogen atoms and the extranuclear amino groups of adenine and guanine.⁹ The biological significance of these purine adducts remains to be clarified. In vivo, acrylamide is biotransformed to its epoxide, glycidamide (GA).¹⁰ This biotransformation of acrylamide to GA is mediated by cytochrome P450 2E1 (CYP2E1).¹¹ GA has been reported to be 100–1000 times more reactive with DNA than acrylamide, and GA is considered as genotoxic in a variety of test systems.¹² DNA adducts formation in adult mice from acrylamide treatment showed a supralinear dose–response relationship, which was consistent with the saturation of oxidative biotransformation of acrylamide at higher doses.¹³

There is evidence that the genotoxicity of acrylamide predominantly results from metabolic conversion into its epoxide derivative GA,^14,15 due to the formation of GA-DNA adducts following the administration of acrylamide.^13,16,17 Acrylamide was a clear tumor initiator in several classic tumor ‘initiation-promotion’ studies in mice.^18–20 Several previous studies of the carcinogenicity of acrylamide²¹ indicated that acrylamide caused tumors at multiple sites in mice^18–20 and rats²² when given systemically by various routes.

The aim of this study is to investigate that acrylamide is a multiorgan carcinogen in experimental rat model which presents a potential carcinogenic hazard to humans and also to study the possible mechanism of acrylamide induction of some hormonal disturbance.

Materials and methods

Experimental animals

Forty male Sprague Dawley rats weighing 100–130 g (from the Animal House Colony of the National Research Centre, Cairo, Egypt) were maintained on standard laboratory diet and water ad libitum. After an acclimation period of 1 week, the rats were randomly divided into 4 groups (10 rats/group) and housed in a room maintained at 23 ± 1°C, 40–60% relative humidity and artificially illuminated (12-h dark/light cycle). Group I rats served as control, rats of Groups II, III and IV were given acrylamide orally by stomach tube at doses of 5, 10 and 15 mg/kg/day, respectively (Merck-Schuchardt Chemical Company, Hohenbrunn, Germany), dissolved in water for 8 weeks.

Sample collection

At the end of the experimental period, the animals were kept fasting for 12 hours and the blood samples were collected from the retro-orbital venous plexus under diethyl ether anesthesia. Blood samples from each animal were collected in tubes containing EDTA and plasma was separated after centrifugation at 3000 rpm for 15 minutes at 4°C. Plasma was used for the determination of carcino embryonic antigen (CEA), malondialdehyde (MDA), total antioxidant, free and total testosterone, triiodothyronine (T₃), 3,5,3′,5′-tetraiodothyronine (T₄) and corticosterone levels. After blood collection, the rats were killed; the whole testis, thyroid and adrenal glands of each animal were washed with isotonic saline for histopathological investigation.

Biochemical analysis of plasma

Assay of CEA

Enzyme-linked immunosorbent assay (ELISA) was used for quantitative determination of CEA in plasma using kit purchased from Medical Technology Promedt Consulting (GmbH), Germany.²³

MDA measurement

Plasma MDA was assayed by thiobarbituric acid method as described by Esterbauer and Cheeseman.^24,25

Assay of total antioxidant

Quantitative determination of total antioxidant in plasma was carried out by colorimetric method using the kit purchased from Biodiagnostic, Egypt, by the reaction of antioxidants in the sample with a defined amount of exogenously provided hydrogen peroxide (H₂O₂). The antioxidants in the sample eliminate a certain amount of the provided H₂O₂. The residual H₂O₂ was determined colorimetrically by an enzymatic reaction that involved the conversion of 3,5,dichloro-2-hydroxybenzensulphonate into a colored product.²⁶

Hormonal assays

ELISA procedure was used for quantitative determination of plasma-free testosterone²⁷ (Diagnostics Biochem, Canada), total testosterone²⁸ (Dima Gesellschaft Fur Diagnostika [GmbH], Germany), T₃ ²⁹, T₄ ³⁰ (International immuno Diagnostics Co., CA, USA) and corticosterone³¹ (kit purchased from Calbiotech Inc).

Histopathological investigation

The testis, thyroid and adrenal gland samples of five rats in each group were fixed in 10% buffered formalin solution, dehydrated, cleared and embedded in paraffin wax. Paraffin sections of 5-μm thickness were prepared and stained with hemotoxylin–eosin.³² All stained slides were viewed using Olympus microscope (Olympus BX51, Korea) and the images were captured by a digital camera (Cannon 620, Korea). Brightness and contrast were adjusted using Adobe Photoshop software (version 4.0.1; Adobe Systems, Mountain View, CA, USA).

Statistical analysis

Data are presented as mean ± standard deviation (SD) and mean ± standard error (SE). One-way analysis of variance (ANOVA) followed by Tukey multiple comparison method was carried out to compare the mean value of different groups using SPSS 7.5 student version. Comparisons were made between Group I versus Groups II, III and IV, and between Group II versus Groups III and IV. p < 0.05 was considered statistically significant.

Results

There was significant decrease in body weight in rats treated with 5, 10 and 15 mg/kg of acrylamide (Groups II–IV) compared to control rat (Group I), with p value < 0.001, with a percentage change of −10.35%, −11.07% and −12.06%, respectively (Table 1 and Figure 1). On the other hand, plasma CEA level was 2.7-, 3.3- and 4.2-fold higher in rats of Groups II, III and IV compared to rats in the control group, with p value < 0.001 (Table 2). Plasma MDA was significantly increased in Groups II, III and IV compared to control (Group I) with p value < 0.001, with a percentage change of 13.24%, 15.05% and 18.04%, respectively, but there was no significant difference between groups. Plasma total antioxidant had significant decrease in Groups II (p value < 0.05), III and IV (p value < 0.01) when compared to the control Group I with a percentage change of −18.5%, −29.53% and −37.01%, respectively. On the other hand, there was no significant difference in plasma total antioxidant between the groups (Table 2). There was significant decrease in each of plasma-free and total testosterone, T₃, T₄ and corticosterone in all groups in comparison with the control rats (Table 3 ). On the other hand, there was no significant difference in plasma total testosterone and T₃ between Group II and Group III and between Group III and Group IV. There was no significant difference in plasma-free testosterone and T₄ between Group III and Group IV, but there was significant decrease in Group III in comparison with Group II, with p value < 0.01. There was significant decrease in plasma corticosterone in Group III in comparison with Group II and in Group IV in comparison with Group III, with p value < 0.001 and 0.01, respectively.

Table 1.

Mean ± S.D. of rat body weights before and after experiment in the different groups^a

Groups Parameters	Group I (control)	Group II (5 mg/kg acrylamide treated)	Group III (10 mg/kg acrylamide treated)	Group IV (15 mg/kg acrylamide treated)
Body weight before experiment (g)	141.7 ± 5	140.8 ± 6	142.5 ± 4	143.4 ± 7
Body weight after experiment (g)	152.6 ± 4	136.8 ± 6^b	135.7 ± 5^b	134.2 ± 5^b
Percentage change		−10.35%	−11.07%	−12.06%

^a p ≤ 0.05 is considered significant, p > 0.05 is considered nonsignificant (NS). Groups II, III, and IV compared with control group I.

^b p < 0.001.

Figure 1.

The mean ± standard error (SE) weights (mg) of rat groups before and after the experiment.

Table 2.

Mean ± S.E. for rat plasma CEA, MDA and total antioxidants levels in the different groups^a

Groups Parameters	Group I (control)	Group II (5 mg kg acrylamide treated)	Group III (10 mg/kg acrylamide treated)	Group IV (15 mg/kg acrylamide treated)
CEA (ng/ml)	2.7 ± 0.61	10.05 ± 0.29^{b, e}	11.7 ± 0.31^{b, c, e}	14.02 ± 0.4^{b, d, e}
Percentage change		272.22%	333.33%	419.26%
MDA (nmol/ml)	17.68 ± 0.33	20.02 ± 0.17^{b, e}	20.34 ± 0.23^{b, e, c}NS	20.87 ± 0.23^{b, e, d}NS
Percentage change		13.24%	15.05%	18.04%
Total antioxidant (mM/L)	2.54 ± 0.16	2.07 ± 0.17^{b, f}	1.79 ± 0.16^{b, g}.^cNS	1.6 ± 0.16^{b, g, d}NS
Percentage change		−18.5%	−29.53%	−37.01%

CEA: carcino embryonic antigen, MDA: malondialdehyde.

^a p ≤ 0.05 is considered significant; p > 0.05 is considered nonsignificant (NS).

^b Groups compared with control Group I.

^c Group III compared with Group II.

^d Group IV compared with Group III.

^e p < 0.001.

^f p < 0.05.

^g p < 0.01.

Table 3.

Mean ± S.E. for rat plasma-free and total testosterone, T3, T4 and corticosterone level in the different groups^a

Groups Parameters	Group I (control)	Group II (5 mg/kg acrylamide treated)	Group III (10 mg/kg acrylamide treated)	Group IV (15 mg/kg acrylamide treated)
Free testosterone (pg/ml)	29.7 ± 1.19	9.24 ± 0.23^{b, e}	8.19 ± 0.2^{b, c, e}	7.65 ± 0.21^{b, e, c}NS
Percentage change		−68.89%	−72.42%	−74.24%
Total testosterone (ng/ml)	3.61 ± 0.19	1.12 ± 0.09^{b, e}	0.96 ± 0.07^{b, e, c}NS	0.77 ± 0.08^{b, e, c}NS
Percentage change		−68.98%	−73.41%	−78.67%
T₃ (ng/ml)	3.11 ± 0.21	2.35 ± 0.17^{b, f}	2.24 ± 0.17^{b, f, c}NS	2.1 ± 0.16^{b, e, c}NS
Percentage change		−24.44%	−27.97%	−32.48%
T₄ (μg/dl)	9.76 ± 0.15	8.25 ± 0.13^{b, e}	7.61 ± 0.15^{b, e, c, f}	7.41 ± 0.16^{b, e, c}NS
Percentage change		−15.47%	−22.03%	−24.08%
Corticosterone (ng/ml)	15.6 ± 1.07	8.77 ± 0.27^{b, e}	7.41 ± 0.22^{b, c, e}	6.51 ± 0.25^{b, e, c, f}
Percentage change		−43.78%	−52.5%	−58.27%

T₃: triiodothyronine, T₄: 3,5,3′,5′-tetraiodothyronine.

^a p ≤ 0.05 is considered significant; p > 0.05 is considered nonsignificant (NS).

^b Groups compared with control Group I.

^c Group III compared with Group II.

^d Group IV compared with Group III.

^e p < 0.001.

^f p < 0.01.

Morphologically, the testis of the control rats showed normal arrangement of seminiferous tubules (Figure 1A). Figure 2B showed damages with degenerated spermatogonia in the seminiferous tubules in Group II; while in Group III, the seminiferous tubules showed damages associated with absence of cells and the lumen was empty without sperms (Figure 2C). Testes in Group IV showed damages with the arrested spermatogenesis at the level of primary spermatocytes in the seminiferous tubules; while it was absent in the rest of the cells (Figure 3D ).

Figure 2.

Photomicrographs of transverse section of testis stained with hemotoxylin–eosin (H&E). (A) Control rat. (B) Rats treated with 5 mg/kg/day. (C) Rats treated with 10 mg/kg/day of acrylamide. (D) Rat treated with 15 mg/kg/day of acrylamide (×100).

Figure 3.

Photomicrographs of transverse section of adrenal cortex stained with hemotoxylin–eosin (H&E). (A) Control rat. (B) Rats treated with 5 mg/kg/day. (C) Rats treated with 10 mg/kg/day of acrylamide. (D) Rats treated with 15 mg/kg/day of acrylamide (×100).

Photomicrograph of transverse section of thyroid gland of control rat showed thyroid follicles lined with tall cuboidal vacuolated cells and their lumen of the follicles is filled with acidophilic colloid with serrated edge (Figure 4A ); while Group II showed collapsed colloid in some thyroid follicles as shown in Figure 4B. While in Group III the small-sized thyroid follicles had colloid with less serrated edge, the follicles were lined with flat epithelial cells (Figure 4C); while the thyroid gland in Group IV had small-sized thyroid follicles that were lined with flat epithelial cells as shown in Figure 4D.

Figure 4.

Photomicrographs of transverse section of thyroid gland stained with hemotoxylin–eosin (H&E). (A) Control rat (×100). (B) Rats treated with 5 mg/kg/day of acrylamide (×20). (C) Rats treated with 10 mg/kg/day of acrylamide (×10). (D) Rats treated with 15 mg/kg/day of acrylamide (×10).

Photomicrograph of transverse section of adrenal cortex of control rat showed zona glomerulosa, zona fasiculata and zona reticulata as shown in Figure 3A; while the adrenal cortex in Group II showed vacuolation of the cytoplasm of fasciculata cells. Many of acidophilic cells can be observed as shown in Figure 3B; while Group III showed separation of the cells of zona fasciculata and empty spaces between it. Notice the disappearance of its nuclei as shown in Figure 3C; while Group IV showed vacuolation in the cytoplasm of fasciculate cells. Many of it showed acidophilic stain as shown in Figure 3D.

Discussion

The metabolism of acrylamide in the body may result in the generation of reactive oxygen species (ROS) which plays a role in the oxidative stress of acrylamide and causes oxidative DNA damage, which may in turn play a role in its carcinogenicity.³³ Moreover, lipid peroxidation (LP) is one of the main manifestations of oxidative damage and has been found to play an important role in the toxicity and carcinogenicity of many carcinogens.³³

Wang et al.³⁴ and Mei et al.³⁵ used 5 and 10 mg/kg/day of acrylamide on male Sprague Dawley and big blue rats, respectively, their results were consistent with acrylamide (AA) being a gene mutagen in the rats via metabolism of glycidamide (GA). In this study, the doses of acrylamide treatment were 5, 10 and 15 mg/kg/day and it has been found that the current study deals with the carcinogenicity of acrylamide and interaction between acrylamide and hormonal disorders in male rats. CEA³⁶ is a cell surface glycoprotein. It was elevated in patients with many cancers and the elevation of plasma levels of CEA are related to the stage and the extent of the tumor. Animals that are orally treated differently with acrylamide showed increase in CEA compared with control animals; those rats treated with 5 mg/kg/day of acrylamide showed increase in the CEA levels than the control; while rats that were treated with 10 mg/kg/day of acrylamide showed an increase in CEA than those treated with 5 mg/kg/day of acrylamide. The rats that were treated with 15 mg/kg/day of acrylamide showed an increase in CEA levels over rats that were treated with 10 mg/kg/day of acrylamide, and this improves the carcinogenicity of acrylamide and thus the damage caused by acrylamide takes place in dose-dependant manner.

The levels of oxidative stress indices and LP (MDA) in the plasma of rats treated with acrylamide were significantly increased while total antioxidant activity was significantly decreased compared with their levels in the controls. These results clearly indicated that total antioxidant activity suppresses the formation of oxygen free radicals in the rat body. The decrease in total antioxidant activity in plasma of rats treated with acrylamide might indirectly lead to an increase in oxidative DNA damage.³⁷ Mannaa et al.³⁸ showed that treatment with acrylamide caused a significant decrease in total antioxidant and significant increase in LP in brain homogenate in female rats. There was a significant decrease in thiol groups in lungs, kidney, brain, testis and liver homogenates in male rats treated with acrylamide in a dose-dependent manner.³⁹ Glutathione is the principal thiol and redox buffer in mammalian cells, while serum albumin is the principal protein in the plasma fraction of blood.⁴⁰

The present study indicated that testis is a target organ of acrylamide action as it caused severe damage in seminiferous tubules and caused decreases in plasma-free and total testosterone in a dose-dependent manner and this is in agreement with Yang et al.⁴¹ This study showed that the levels of free and total testosterone were significantly decreased in the plasma of rats treated with 5, 10 and 15 mg/kg/day of acrylamide compared to controls in contrast with the results of Wang et al.³⁴

The present results revealed that acrylamide induces severe stress on the endocrine function in rats, which included thyroid, adrenal cortex and adrenal medulla. Shelby⁴² studied the effects of acrylamide on endocrine glands and concluded that acrylamide induced thyroid follicle adenomas and carcinomas in female rats. In agreement with our results, Khan et al.⁴³ reported that thyroxine (T₄) was decreased in female rats as an early response to acrylamide toxicity, and the doses were 2 and 15 mg/kg/day. The decrease in levels of T₃ and T₄ in a dose-dependent manner clearly indicated that acrylamide caused hypothyroid gland activity. Friedman et al.²² exhibited no evidence of dose-related thyroid follicular cell hyperplasia, a hallmark of the thyroid hormone disruption mechanism. Thus, the available data do not support a nongenotoxic, proliferative mechanism of thyroid tumor induction for acrylamide. Khan et al.⁴³ reported that the morphometry of the thyroid glands showed a significant decrease in the colloid area and a significant increase in cell height of the thyroid follicles in acrylamide-treated rats for 2 and 7 days, respectively. Mannaa et al.³⁸ showed that treatment with acrylamide 50 mg/kg body weight for 11 days caused a significant decrease in serum T₃ and T₄ in female rats, which was in agreement with our results which revealed that the levels of T₃ and T₄ was significantly decreased in the plasma of rats treated with 5, 10 and 15 mg/kg/day of acrylamide compared with the control. On the other hand, Bowyer et al.⁴⁴ studies showed virtually no evidence for systematic alteration of the hypothalamic–pituitary–thyroid axis and does not support hormone dysregulation as a plausible mechanism for AA-induced thyroid cancer in the Fischer 344 rat. Specifically, there were no significant differences in (1) mRNA levels in hypothalamus or pituitary for thyrotropin-releasing hormone (TRH), thyroid-stimulating hormone (TSH), thyroid hormone receptor alpha and beta, as well as 10 other hormones or releasing factors; (2) mRNA levels in thyroid for thyroglobulin, thyroid peroxidase, sodium iodide symporter, or type I deiodinases; (3) serum TSH or T₃ levels (T₄ was decreased at high dose only).

Mannaa et al.³⁸ showed that treatment with acrylamide caused a significant decrease in serum corticosterone in female rats. The present study revealed that acrylamide induces severe stress on the adrenal gland resulting in a significant decrease in plasma corticosterone in a dose-dependent manner, which suggested that adrenal cortex undergoes severe effects and/or acrylamide induces disturbances in the hypothalamic–pituitary–adrenal relationships.⁴⁵ Moreover, Erdreich and Friedman⁴⁶ stated that acrylamide administration increased the incidence of several tumor types in rats including adrenal pheochromocytomas.

In conclusion, this study indicated that acrylamide caused increase in LP and decrease in total antioxidant activity therefore may increase cancer risk. Acrylamide may cause endocrine disturbances to the testis, thyroid and adrenal glands. It also may cause tumor in experimental animals especially to endocrine systems and this may be a potential carcinogenic hazard to human.

Footnotes

Acknowledgement

We express sincere thanks to Prof. Dr Hanaa H Ahmed, Hormones Department, National Research Center and Dr Abdel Razik Hussein Farrag, Researcher of Pathology, Medical Research Division for their help in histological and histochemical investigations and their assistance in this manuscript.

This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

References

Tareke

Rydberg

Karlsson

Eriksson

Tornqvist

Acrylamide: a cooking carcinogen?

Chem Res Toxicol 2000; 13: 517–522.

Tareke

Rydberg

Karlsson

Eriksson

Tornqvist

Analysis of acrylamide, a carcinogen formed in heated foodstuffs. J Agric Food Chem 2002; 50: 4998–5006.

Rosen

Hellenas

Analysis of acrylamide in cooked foods by liquid chromatography tandem mass spectrometry. Analyst 2002; 127: 880–882.

Mottram

Wedzicha

Dodson

AT.

Acrylamide is formed in the Maillard reaction. Nature 2002; 419: 448–449.

Rydberg

Eriksson

Tareke

Karlsson

Ehrenberg

Tornqvist

Investigations of factors that influence the acrylamide content of heated foodstuffs. J Agric Food Chem 2003; 51: 7012–7018.

Yaylayan

Wnorowski

Perez Locas

CP.

Why asparagine needs carbohydrates to generate acrylamide. J Agric Food Chem 2003; 51: 1753–1757.

Sorgel

Weissenbacher

Kinzig-Schippers

Hofmann

Illauer

Skott

. Acrylamide: increased concentrations in homemade food and first evidence of its variable absorption from food, variable metabolism and placental and breast milk transfer in humans. Chemotherapy 2002; 48: 267–274.

Friedman

Chemistry, biochemistry, and safety of acrylamide: a review. J Agric Food Chem 2003; 51: 4504–4526.

Solomon

Fedyk

Mukai

Segal

Direct alkylation of 2′-deoxynucleosides and DNA following in vitro reaction with acrylamide. Cancer Res 1985; 45: 3465–3470.

10.

Bergmark

Calleman

Costa

LG.

Formation of hemoglobin adducts of acrylamide and its epoxide metabolite glycidamide in the rat. Toxicol Appl Pharmacol 1991; 111: 352–363.

11.

Sumner

Fennell

Moore

Chanas

Gonzalez

Ghanayem

BI.

Role of cytochrome P450 2E1 in the metabolism of acrylamide and acrylonitrile in mice. Chem Res Toxicol 1999; 12: 1110–1116.

12.

Paulsson

Granath

Grawe

Ehrenberg

Tornqvist

The multiplicative model for cancer risk assessment: application of acrylamide. Carcinogen 2001; 22: 816–819.

13.

Gamboa da Costa

Churchwell

Hamilton

Von Tungeln

Beland

Marques

. DNA adduct formation from acrylamide via conversion to glycidamide in adult and neonatal mice. Chem Res Toxicol 2003; 16: 1328–1337.

14.

Twaddle

Hamilton

Gamboa da Costa

Churchwell

Beland

Doerge

DR.

Determination of acrylamide and glycidamide serum toxicokinetics in B6C3F1 mice using LC-ES/MS/MS. Cancer Lett 2004; 207: 9–17.

15.

Doerge

Young

Mc Daniel

Twaddle

Churchwell

MI.

Toxicokinetics of acrylamide and glycidamide in Fischer 344 rats. Toxicol Appl Pharmacol 2005; 208: 199–209.

16.

Doerge

da Costa

Mc Daniel

Churchwell

Twaddle

Beland

FA.

DNA adducts derived from administration of acrylamide and glycidamide to mice and rats. Mutat Res 2005; 580: 131–142.

17.

Ghanayem

Witt

El-Hadri

Hoffler

Kissling

Shelby

. Comparison of germ-cell mutagenicity in male CYP2E1-null and Wild-type mice treated with acrylamide: evidence supporting a glycidamide-mediated effect. Biol Reprod 2005; 72: 157–163.

18.

Bull

Robinson

Laurie

Stoner

Greisiger

Meier

. Carcinogenic effect of acrylamide in SENCAR and A/J mice, Cancer Res 1984; 44: 107–111.

19.

Bull

Robinson

Stober

JA.

Carcinogenic activity of acrylamide in the skin and lung of Swiss-ICR mice, Cancer Lett 1984; 24: 207–212.

20.

Robinson

Bull

Knutsen

Shields

Stober

A combined carcinogen bioassay utilizing both the lung adenoma and skin papilloma protocols. Environ Health Perspect 1986; 68: 141–146.

21.

Rice

JM.

The carcinogenicity of acrylamide. Mutat Res 2005; 580: 3–20.

22.

Friedman

Dulak

Stedham

MA.

A lifetime oncogenicity study in rats with acrylamide, Fundam Appl Toxicol 1995; 27: 95–105.

23.

Wild

The immunoassay handbook. Stockton Press, NY, USA, 1994, p.444.

24.

Esterbauer

Cheeseman

KH.

Determination of aldehydic lipid peroxidation products: malonaldehyde and 4-hydroxynonenal. Methods Enzymol 1990; 186: 407–421.

25.

Zima

Stipek

Crkovska

Platenik

Measurement of lipid peroxidation products in biological samples by spectrophotometric and HPLC assay. Klin Biochem Metab 1995; 3: 98–102.

26.

Koracevic

Djordjevic

Andrejevic

Cosic

Method for the measurement of antioxidant activity in human fluids. J Clin Pathol 2001; 54: 356–361.

27.

Nazian

SJ.

Concentrations of free testosterone, total testosterone, and androgen binding protein in the peripheral serum of male rats during sexual maturation. J Androl 1986; 7: 49–54.

28.

Chen

Bookstein

Meldrum

DR.

Diagnosis of a testosterone-secreting adrenal adenoma by selective venous catheterization. Fertil Steril 1991; 55: 1202–1203.

29.

Larsen

PR.

Triiodothyronine: review of recent studies of its physiology and pathophysiology in man. Metabolism 1972; 21: 1073–1092.

30.

Wistom

GB.

Enzyme-immunoassay. Clin Chem 1976; 22: 1243.

31.

Chemow

Alexander

Smallridge

Thompson

Cook

Beardsley

. Hormonal responses to graded surgical stress. Arch Intern Med 1987; 147: 1273–1278.

32.

Drury

RAB

Wallington

EA.

Preparation and fixation of tissues in Carleton’s histological technique. 4th ed. Oxford University Press, 1980, pp.36–56.

33.

Bergmark

Calleman

Costa

LG.

Formation of hemoglobin adducts of acrylamide and its epoxide metabolite glycidamide in the rat. Toxicol Appl Pharmacol 1991; 111: 352–363.

34.

Wang

Huanga

Lie

Hutzc

. Reproductive toxicity of acrylamide-treated male rats. Reprod Toxicol 2010; 29: 225–230.

35.

Mei

McDaniel

Dobrovolsky

Guo

Shaddock

Mittelstaedt

. The genotoxicity of acrylamide and glycidamide in big blue rats. Toxicol Sci 2010; 115: 412–421. Epub 3 March 2010.

36.

Yamao

Kai

Kazami

Koizumi

Handa

Takemoto

. Tumor markers CEA, CA19-9 and CA125 in monitoring of response to systemic chemotherapy in patients with advanced gastric cancer. Jpn J Clin Oncol 1999; 29: 550–555.

37.

Abdel-Wahhab

Ahmed

HH.

Protective effects of Korean Panax ginseng against chromium VI toxicity and free radical generation in rats. J Ginseng Res 2004; 28: 11–17.

38.

Mannaa

Abdel-Wahhab

Ahmed

Park

MH.

Protective role of Panax ginseng extract standardized with ginsenoside Rg3 against acrylamide-induced neurotoxicity in rats. J Appl Toxicol 2006; 26: 198–206.

39.

Yousef

El-Demerdash

FM.

Acrylamide-induced oxidative stress and biochemical perturbation in rats. Toxicology 2006; 219: 133–141.

40.

Tong

Cornwell

Means

GE.

Reactions of acrylamide with glutathione and serum albumin. Toxicol Lett 2004; 147: 127–131.

41.

Yang

Lee

Jin

Choi

Lee

Han

. Toxicological effects of acrylamide on rat testicular gene expression profile. Reprod Toxicol 2005; 19: 527–534.

42.

Shelby

MK.

Panel report on the reproductive and developmental toxicity of acrylamide. Cancer for the evaluation of risk to human reproduction. National Toxicology Program, US Department of Health and Human Services. NTP-CERHR- Acrylamide-04. 2004.

43.

Khan

Davis

Foley

Friedman

Hansen

LG.

Changes in thyroid gland morphology after acute acrylamide exposure. Toxicol Sci 1999; 47: 151–157.

44.

Bowyer

Latendresse

Delongchamp

Muskhelishvili

Warbritton

Thomas

. The effects of subchronic acrylamide exposure on gene expression, neurochemistry, hormones, and histopathology in the hypothalamus-pituitary-thyroid axis of male Fischer 344 rats. Toxicol Appl Pharmacol 2008; 230: 208–215. Epub 18 March 2008.

45.

Parker

LN.

Control of adrenal androgen secretions. Endocrinol Metab Clin 1991; 20: 401–422.

46.

Erdreich

Friedman

MA.

Epidemiologic evidence for assessing the carcinogenicity of acrylamide. Regul Toxicol Pharmacol 2004; 39: 150–157.

Effect of acrylamide on some hormones and endocrine tissues in male rats

Abstract

Keywords

Introduction

Materials and methods

Experimental animals

Sample collection

Biochemical analysis of plasma

Assay of CEA

MDA measurement

Assay of total antioxidant

Hormonal assays

Histopathological investigation

Statistical analysis

Results

Discussion

Footnotes

Acknowledgement

References