TOXICOLOGY
AND
Tissue
APPLIED
Enzyme
PHARMACOLOGY
32,5--l
0 (1975)
Changes in Pregnant Rats Treated with Epoxy Resin (Epidian 5) or Triethylenetetramine Stabilizer
Topically
JANUSZ WOYTO~~, JERZY SZACKI, ALEK~ANDRA WOYTOI?, MARIA WARWAS AND WANDA DOBRYSZYCKA Obstetrical Clinic of the Institute of Gynecology and Obstetrics, Dermatological Clinic and Department of Clinical Investigation, Institute of Bio-Pharmacy, Medical Academy of Wroclaw, Poland Received March 20,1974; accepted August 27,1974
Tissue Enzymes Changes in Pregnant Rats Treated Topically with Epoxy Resin(Epidian 5) or Triethylenetetramine Stabilizer. WO~TO&, J., SZACKI, J., Worro~G, A., WARWAS, M., AND D0~Rysz~cK.4, W. (1975). Toxicol. Appl. Pharmacol. 32, 5-10. Activities of y-glutamyltranspeptidasein kidney homogenates,aspartateand alanine aminotransferasesin liver homogenates,and acetylcholinesterasein brain homogenatesfrom pregnant and nonpregnant rats treated dermally with the epoxy resin Epidian 5 or a triethylenetetramine stabilizer were studied. In nonpregnant rats, treatment with resin or stabilizer induced an increasein y-glutamyltranspeptidase activity in the kidneysandboth aminotransferases in the liver. Acetylcholinesterasesactivity in the brain was inhibited only by the stabilizer. In the group of pregnant rats, y-glutamyltranspeptidase activity was increasedby administration of Epidian 5 only; aspartate aminotransferaseactivity in the liver wasinhibited in rats treated dermally with the epoxy resin or stabilizer. Morphological changesin the internal organsof nonpregnantand pregnantrats were similar after absorption of epoxy resin or stabilizer, consistingof hyperemiaof the liver and kidneys, and in the dermis and subcutaneoustissuesof inflammatory infiltrates composed of plasmocytes, leucocytes, and lymphocytes; brain tissue showedno changes. The most widely used compounds in the production of plastics are epoxy resinswhich, combined with suitable stabilizers, can be molded on an industrial scale. A strong irritant action on the skin of persons employed in the production of plasticizers was reported by numerous authors (Ammer, 1970; Kastner and Bien, 1969; See1and Umlauf, 1969) but it is still a matter of interest whether a resin or a stabilizer is mainly responsiblefor the observed pathological changes. The subject of our study has been epoxy resin Epidian 5l with the following formula :
1Chemicallypure,ChemicalLaboratoriesin Copyright 0 1975 by Academic Press. Inc. All rights of reproduction in any form reserved. Printed in Great Britain
Szarzyn, 5
Poland.
6
WOYTOti
ET AL.
and its stabilizer triethylenetetramine (TETA).’ The aim of our studies has been an observation of biochemical changes caused by these compounds when absorbed through the skin of pregnant and nonpregnant animals. In the present paper the morphology of some parenchymatous organs and the activity of enzymes which might characterize metabolic disorders at the cellular level caused by the toxic action of epoxy resin or its stabilizer, were studied. The following enzymes were examined: (1) y-glutamyltranspeptidase (GGTP), which has been considered as an enzyme characterizing renal function since its activity in the kidneys is ten times higher than in the liver. (2) Aspartate (AspAT) and alanine (AlAT) aminotransferases were chosen to characterize liver function. (3) An investigation of the sensitivity of acetylcholinesterase (Achase) to the compounds was considered of interest because this enzyme, which occurs in large amounts in the gray substance of the brain and is involved in processes of neurotransmission, is particularly sensitive to different inhibitors. METHODS
Experiments were carried out with 60 healthy, sexually mature female albino rats of the Wistar strain, of mean body weight about 190 g, fed a standard laboratory diet and water ad lib. The animals were divided into groups of ten rats each: Group Group Group Group Group Group
I-nonpregnant control for groups III and IV. II-pregnant control for groups V and VI. III-nonpregnant rubbed with Epidian 5. IV-nonpregnant rubbed with TETA. V-pregnant rubbed with Epidian 5. VI-pregnant rubbed with TETA.
Pregnancy was determined by cytohormonal smears. The examined compounds were rubbed into the skin of the animals daily for 17 days. The technique of rubbing Epidian 5 or TETA into the skin of the rats was as follows: hair was shaved out from two symmetric areas, 2 x 2 cm, on the backs of the rats. On one of the shaved fields one drop (mean weight for one drop of resin, 6.8 mg; for one drop of TETA stabilizer, 4.06 mg) of the studied compound was rubbed in, the other one remaining free as a control. This area of the rat’s skin was chosen to prevent licking by the test animals. During the experiment each rat was placed in a separate cage. Changes on the skin and general conditions of the animals were observed. On the 17th day of the experiment, the animals were anesthetized with ether, weighed, and bled by intracardiac puncture. Autopsies were performed, and pieces of kidney, liver, and brain were transferred to cold 0.9 ‘A NaCl solution and were used for the preparations of homogenates. For histopathological analysis the selected tissues were : kidney, liver, brain, and skin from the treated area. The organs were fixed in 5% formalin; then paraffin sections stained with eosin and hematoxylin were made. Accurately weighed samples of approximately 100 mg of liver were homogenized in 10 ml of 0.1 M phosphate buffer, pH 7.4; 100 mg samples of kidney were homogenized in 5 ml of 0.1 M Tris-HCI buffer, pH 9.0; 500 mg of brain were homogenized in 1.5 ml of 0.1 M Verona1 buffer, pH 8.2. Homogenates were centrifuged 10 min at 10,000 rpm, and the enzyme activity was assayed in the supernatants. In the kidney extracts, GGTP
EPOXIDE
AND
STABILIZER
ON RATS
I
activity was assayed according to Orlowski and Meister (1965) and expressed in micromol of substrate decomposed by 1 g of tissue/min at 37°C. In liver extracts, aminotransferases were determined by the method of Reitman and Frankel(1957), and their activities were given in mol of pyruvic acid liberated by 1 g of wet tissue after incubation at 37°C for 60 min for AspAT, and 30 min for AlAT, respectively. In brain extracts, Achase was measured by the method of De la Huerga et al. (1952) in terms of micromol of acetylcholine decomposed by 1 g of wet tissue/hr at 37°C. RESULTS
In the group of nonpregnant rats treated with Epidian 5, mean body weight dropped from an average weight of 190 g before the experiment to 120 g after its termination, with considerable emaciation of the animals. In all the rats after 5 days of rubbing with the compounds the skin showed inflammatory changes in the form of erythema, edema, and superticial erosions. Microscopic examination of the liver and kidneys revealed only hyperemia. The brain tissue appeared normal.
FIG. 1. Section of skin from a rat treated with epoxy resin Epidian 5. Inflammatory infiltration in the dermis and subcutaneous tissue, composed mainly of plasmocytes, leukocytes, and lymphocytes (x240).
In the group of pregnant rats treated with Epidian 5, mean body weight increased slightly, from 190 g before the experiment to 200 g, while pregnancy itself was found to result in control pregnant rats in an increase of body weight up to 250 g. The rats of the group showed atrophy of the adipose tissue, the skin being flabby and the adipose tissue hardly palpable. The skin changes and those of internal organs were identical with those seen in the nonpregnant rats treated with Epidian 5. In the group of nonpregnant rats treated with TETA stabilizer, mean body weight dropped from 190 to 115 g, and in pregnant rats increased slightly to 200 g.
a
WOYTOfi
ET AL.
Morphological and microscopic changes in the internal organs of nonpregnant and pregnant rats treated with Epidian 5 or TETA were identical : Liver and kidneys : hyperemia. Skin: in the cutis vera and subcutaneous tissue, inflammatory posed mainly of plasmocytes, leucocytes, and lymphocytes. Brain : no changes.
infiltration
com-
The histological pattern of the skin is shown in Fig. 1. The results of enzyme determinations in the tissue of parenchymatous organs from pregnant and nonpregnant rats treated with Epidian 5 or TETA are summarized in Table 1. In nonpregnant rats, treatment with Epidian 5 or stabilizer significantly raised activities of GGTP in the kidneys and both aminotransferases in the liver. Achase activity in the brain was inhibited only in the group treated with TETA. Entirely different results were obtainedin the group ofpregnant rats. The only changes observed were lowered AspAT activity in the livers of rats treated with epoxy resin or stabilizer, and increased GGTP activity in the kidneys of rats treated with Epidian 5. DISCUSSION
Results of the present paper demonstrate toxicity of the epoxy resin Epidian 5 and triethylenetetramine (TETA) stabilizer absorbed through the skin. Both compounds were found to cause injury of the epidermis and dermis, and to induce inflammation with superficial and deep erosions. Absorption of the compounds through the injured skin caused considerable changes in the parenchymatous organs in the form of hyperemia of liver and kidneys. Disorders in cell metabolism were manifested by increased GGTP activity in the kidneys and aminotransferase activities in the liver, and lowered Achase activity in the brain. The enzymatic changes were more pronounced in the nonpregnant as compared with pregnant rats, in agreement with results of a previous study (Dobryszycka et al., 1974) in which several biochemical serum constituents were determined in rats treated in the same way with Epidian 5 or TETA. It should be emphasized that the analysis of acute phase factors (seromucoid, haptoglobin, sialic acid) and serum enzymes in the previous study showed different effects of the same toxic compound in pregnant and nonpregnant rats. A similar phenomenon occurred with tissue enzymes of rats rubbed with epoxy resin or stabilizer; AspAT activity was found to increase in the livers of nonpregnant rats and to decrease in pregnant ones, respectively. This observation is difficult to explain because AspAT activity in both control groups of pregnant and nonpregnant rats was similar. It is possible that the mechanisms leading to the difference may be only indirectly connected with pregnancy, and stem largely from disorders in the regulatory mechanism of sex hormones. According to Chen et al. (1973) administration of tetrachlorobiphenyls to male rats induced aniline hydroxylase and ethylmorphine N-demethylase activities, but in female rats decreased both enzyme systems. It seems possible that the different response of pregnant and nonpregnant rats to toxic compounds in the present experiments may have been due to endocrine factor accompanying pregnancy. Comparison of the influence of Epidian 5 and TETA on rats and guinea pigs (Dobryszycka et al., 1974; Woytori et al., 1974) subjected to dermal exposure has shown
26.14 !Z 1.66 14.88 + 0.57
150.00 + 12.47
AspAT AlAT
Achase
Liver
Brain
182.35 + 14.86
32.87 + 0.97” 21.44 + 1.05’
18.37 _+2.24’
Epidian 5 It= 10
a Average values of enzyme activities in units/g of wet tissue, +SD. b Results were analyzed statistically by Student’s f test. cp < 0.01. d0.05 > p > 0.01.
8.75 _+1.16
GGTP
Kidneys
n=lO
Enzymes”~ b
25.70 + 1.66 10.97 + 1.58 186.67 + 25.64
108.70 + 5.35”
8.45 zk 1.05
n=lO
38.67 + 0.68” 20.18 + 2.06’
12.06 + 1.28d
TETA n= 10
175.70 f. 15.07
19.25 & 1.16’ 11.76 + 1.41
12.93 + 1.13d
Epidian 5 n= 10
18.03 k 1.46’ 12.40 + 0.87
11.37 + 1.19
TETA n=lO
170.67 + 13.57
Pregnant rats rubbed with
AND AIAT) AND CHOLINESTERASE (Achase) AC~WIT~ESIN TISSUES OF RESIN EPIDIAN 5 OR TRIETHYLENETETRAMINE (TETA) STABILIZER
(AspAT EPOXY
Nonpregnant rats rubbed with
AMINOTRANSFERASES RATS TREATED WITH
Tissue
-
y-GLUTAMYLTRANSPEPTIDASE (GGTP), NONPREGNANT AND PREGNANT
TABLE I
E 2 Tz t!
2 B z
5
s!
10
WOYTOfi ET AL.
certain interesting relations. Biochemical examinations of serum components revealed a much stronger toxic effect of epoxy resin and stabilizer on pregnant guinea pigs and their fetuses than on rats. In sera of pregnant guinea pigs statistically significant changes were observed in total protein, seromucoid, sialic acid, and haptoglobin levels and in activities of lactate dehydrogenase, leucylnaphthylamidase, GGTP, aminotransferases, acid phosphatase, and cholinesterase, while in sera of nonpregnant guinea pigs changes were found in 3 out of 12 of these biochemical measures. In the course of the experiment 14 out of 22 guinea pigs died with degenerative changes of the placenta resulting in miscarriage or mortification of the fetus. On the other hand, the tissue enzymes, especially in nonpregnant rats, showed more numerous changes than those in nonpregnant guinea pigs. The fact that rats were rubbed with the compounds for 17 days, and guinea pigs, owing to longer duration of pregnancy, 65 days may have been significant. In spite of widely held opinion that pregnancy leads to greater sensitivity to toxic injury (Texler et al., 1970; Woyton et al., 1974) the results of our studies and those of Beliles (1972) seem to indicate that the toxic actions of certain compounds may be different in pregnant vs nonpregnant animals, depending on the species of animals employed. REFERENCES AMMER, D. (1970).Ocenaszkodliwegodzialania naskdreniektorych iywic syntetyzowanychw przemysle.Med. Pracy 21,7-14. BELILES, R. P. (1971).The influenceof pregnancyon the acutetoxicity of variouscompoundsin
mice. Toxicol. Appl. Pharmacol.23,537-W. CHEN, P. R., MEHENDALE, H. M. AND FISHBEIN, L. (1973).Effect of two isomerictetrachlorobiphenylson rats and their hepatic enzymes.Arch. Environ. Contam.Toxicol. 1, 36-47. DE LA HUERGA, J., YESINICK, C. AND POPPER, H. (1952).Calorimetric methodfor the determina-
tion of serumcholinesterase. J. Clin. Pathol. 22, 1126-l 133. DOBRYSZYCKA, W., WARWAS, M., WOYTOI+, A., WOYTOI+, J. AND SZACKI, J. (1974). Serum
proteins and enzymesin pregnant rats treated with epoxy resin Epidian 5 or triethylenetetraaminestabilizer. Arch. Toxicol. 33, 73-80. KXSTNER, D. AND BIEN, E. (1969).Zur Toxicologic von Plastenund ElastenI. Epoxidharze in Lebensmittelindustrieund Medizintechnik. PlasteKautschuk.11, 812-814. OR~WSKI, M. AND MEISTER, A. (1965). Isolation of y-glutamyltranspeptidasefrom hog kidney. J. Biol. Chem.240,339-347. REITMAN, S. ANDFRANKEL,S. (1957).A calorimetric method for the determinationof serum glutamic oxalacetic and glutamic pyruvic transaminases. Amer. J. Clin. Pathol. 28, 56-63. SEEL, H. AND UMLAUF, H. (1969). Gesundeitschaden bie der Verarbeitung von Epoxidharz und ihre Vermeidung.PlasteKautschuk.16, 502-504. TEXLER, K. C., ROMAN, W. AND IRVING, E. A. (1970).The effect of pregnancyon the sensitivity of rabbit liver to diethylnitrosamine.Aust. N.Z. J. Obstet. Gynaec.10, 175-179. WOYTOI$ J., SZACKI, J., DZIOBA, A., WOYTO~~, A., WARWAS, M. AND DOBRYSZYCKA, W. (1974). Biochemicalchangesin the blood of guineapigs exposedto the action of epoxy resinEpidian 5 during pregnancy. Arch. Immunol.Ther. Exp. 22, 129-133.
AND
Tissue
APPLIED
Enzyme
PHARMACOLOGY
32,5--l
0 (1975)
Changes in Pregnant Rats Treated with Epoxy Resin (Epidian 5) or Triethylenetetramine Stabilizer
Topically
JANUSZ WOYTO~~, JERZY SZACKI, ALEK~ANDRA WOYTOI?, MARIA WARWAS AND WANDA DOBRYSZYCKA Obstetrical Clinic of the Institute of Gynecology and Obstetrics, Dermatological Clinic and Department of Clinical Investigation, Institute of Bio-Pharmacy, Medical Academy of Wroclaw, Poland Received March 20,1974; accepted August 27,1974
Tissue Enzymes Changes in Pregnant Rats Treated Topically with Epoxy Resin(Epidian 5) or Triethylenetetramine Stabilizer. WO~TO&, J., SZACKI, J., Worro~G, A., WARWAS, M., AND D0~Rysz~cK.4, W. (1975). Toxicol. Appl. Pharmacol. 32, 5-10. Activities of y-glutamyltranspeptidasein kidney homogenates,aspartateand alanine aminotransferasesin liver homogenates,and acetylcholinesterasein brain homogenatesfrom pregnant and nonpregnant rats treated dermally with the epoxy resin Epidian 5 or a triethylenetetramine stabilizer were studied. In nonpregnant rats, treatment with resin or stabilizer induced an increasein y-glutamyltranspeptidase activity in the kidneysandboth aminotransferases in the liver. Acetylcholinesterasesactivity in the brain was inhibited only by the stabilizer. In the group of pregnant rats, y-glutamyltranspeptidase activity was increasedby administration of Epidian 5 only; aspartate aminotransferaseactivity in the liver wasinhibited in rats treated dermally with the epoxy resin or stabilizer. Morphological changesin the internal organsof nonpregnantand pregnantrats were similar after absorption of epoxy resin or stabilizer, consistingof hyperemiaof the liver and kidneys, and in the dermis and subcutaneoustissuesof inflammatory infiltrates composed of plasmocytes, leucocytes, and lymphocytes; brain tissue showedno changes. The most widely used compounds in the production of plastics are epoxy resinswhich, combined with suitable stabilizers, can be molded on an industrial scale. A strong irritant action on the skin of persons employed in the production of plasticizers was reported by numerous authors (Ammer, 1970; Kastner and Bien, 1969; See1and Umlauf, 1969) but it is still a matter of interest whether a resin or a stabilizer is mainly responsiblefor the observed pathological changes. The subject of our study has been epoxy resin Epidian 5l with the following formula :
1Chemicallypure,ChemicalLaboratoriesin Copyright 0 1975 by Academic Press. Inc. All rights of reproduction in any form reserved. Printed in Great Britain
Szarzyn, 5
Poland.
6
WOYTOti
ET AL.
and its stabilizer triethylenetetramine (TETA).’ The aim of our studies has been an observation of biochemical changes caused by these compounds when absorbed through the skin of pregnant and nonpregnant animals. In the present paper the morphology of some parenchymatous organs and the activity of enzymes which might characterize metabolic disorders at the cellular level caused by the toxic action of epoxy resin or its stabilizer, were studied. The following enzymes were examined: (1) y-glutamyltranspeptidase (GGTP), which has been considered as an enzyme characterizing renal function since its activity in the kidneys is ten times higher than in the liver. (2) Aspartate (AspAT) and alanine (AlAT) aminotransferases were chosen to characterize liver function. (3) An investigation of the sensitivity of acetylcholinesterase (Achase) to the compounds was considered of interest because this enzyme, which occurs in large amounts in the gray substance of the brain and is involved in processes of neurotransmission, is particularly sensitive to different inhibitors. METHODS
Experiments were carried out with 60 healthy, sexually mature female albino rats of the Wistar strain, of mean body weight about 190 g, fed a standard laboratory diet and water ad lib. The animals were divided into groups of ten rats each: Group Group Group Group Group Group
I-nonpregnant control for groups III and IV. II-pregnant control for groups V and VI. III-nonpregnant rubbed with Epidian 5. IV-nonpregnant rubbed with TETA. V-pregnant rubbed with Epidian 5. VI-pregnant rubbed with TETA.
Pregnancy was determined by cytohormonal smears. The examined compounds were rubbed into the skin of the animals daily for 17 days. The technique of rubbing Epidian 5 or TETA into the skin of the rats was as follows: hair was shaved out from two symmetric areas, 2 x 2 cm, on the backs of the rats. On one of the shaved fields one drop (mean weight for one drop of resin, 6.8 mg; for one drop of TETA stabilizer, 4.06 mg) of the studied compound was rubbed in, the other one remaining free as a control. This area of the rat’s skin was chosen to prevent licking by the test animals. During the experiment each rat was placed in a separate cage. Changes on the skin and general conditions of the animals were observed. On the 17th day of the experiment, the animals were anesthetized with ether, weighed, and bled by intracardiac puncture. Autopsies were performed, and pieces of kidney, liver, and brain were transferred to cold 0.9 ‘A NaCl solution and were used for the preparations of homogenates. For histopathological analysis the selected tissues were : kidney, liver, brain, and skin from the treated area. The organs were fixed in 5% formalin; then paraffin sections stained with eosin and hematoxylin were made. Accurately weighed samples of approximately 100 mg of liver were homogenized in 10 ml of 0.1 M phosphate buffer, pH 7.4; 100 mg samples of kidney were homogenized in 5 ml of 0.1 M Tris-HCI buffer, pH 9.0; 500 mg of brain were homogenized in 1.5 ml of 0.1 M Verona1 buffer, pH 8.2. Homogenates were centrifuged 10 min at 10,000 rpm, and the enzyme activity was assayed in the supernatants. In the kidney extracts, GGTP
EPOXIDE
AND
STABILIZER
ON RATS
I
activity was assayed according to Orlowski and Meister (1965) and expressed in micromol of substrate decomposed by 1 g of tissue/min at 37°C. In liver extracts, aminotransferases were determined by the method of Reitman and Frankel(1957), and their activities were given in mol of pyruvic acid liberated by 1 g of wet tissue after incubation at 37°C for 60 min for AspAT, and 30 min for AlAT, respectively. In brain extracts, Achase was measured by the method of De la Huerga et al. (1952) in terms of micromol of acetylcholine decomposed by 1 g of wet tissue/hr at 37°C. RESULTS
In the group of nonpregnant rats treated with Epidian 5, mean body weight dropped from an average weight of 190 g before the experiment to 120 g after its termination, with considerable emaciation of the animals. In all the rats after 5 days of rubbing with the compounds the skin showed inflammatory changes in the form of erythema, edema, and superticial erosions. Microscopic examination of the liver and kidneys revealed only hyperemia. The brain tissue appeared normal.
FIG. 1. Section of skin from a rat treated with epoxy resin Epidian 5. Inflammatory infiltration in the dermis and subcutaneous tissue, composed mainly of plasmocytes, leukocytes, and lymphocytes (x240).
In the group of pregnant rats treated with Epidian 5, mean body weight increased slightly, from 190 g before the experiment to 200 g, while pregnancy itself was found to result in control pregnant rats in an increase of body weight up to 250 g. The rats of the group showed atrophy of the adipose tissue, the skin being flabby and the adipose tissue hardly palpable. The skin changes and those of internal organs were identical with those seen in the nonpregnant rats treated with Epidian 5. In the group of nonpregnant rats treated with TETA stabilizer, mean body weight dropped from 190 to 115 g, and in pregnant rats increased slightly to 200 g.
a
WOYTOfi
ET AL.
Morphological and microscopic changes in the internal organs of nonpregnant and pregnant rats treated with Epidian 5 or TETA were identical : Liver and kidneys : hyperemia. Skin: in the cutis vera and subcutaneous tissue, inflammatory posed mainly of plasmocytes, leucocytes, and lymphocytes. Brain : no changes.
infiltration
com-
The histological pattern of the skin is shown in Fig. 1. The results of enzyme determinations in the tissue of parenchymatous organs from pregnant and nonpregnant rats treated with Epidian 5 or TETA are summarized in Table 1. In nonpregnant rats, treatment with Epidian 5 or stabilizer significantly raised activities of GGTP in the kidneys and both aminotransferases in the liver. Achase activity in the brain was inhibited only in the group treated with TETA. Entirely different results were obtainedin the group ofpregnant rats. The only changes observed were lowered AspAT activity in the livers of rats treated with epoxy resin or stabilizer, and increased GGTP activity in the kidneys of rats treated with Epidian 5. DISCUSSION
Results of the present paper demonstrate toxicity of the epoxy resin Epidian 5 and triethylenetetramine (TETA) stabilizer absorbed through the skin. Both compounds were found to cause injury of the epidermis and dermis, and to induce inflammation with superficial and deep erosions. Absorption of the compounds through the injured skin caused considerable changes in the parenchymatous organs in the form of hyperemia of liver and kidneys. Disorders in cell metabolism were manifested by increased GGTP activity in the kidneys and aminotransferase activities in the liver, and lowered Achase activity in the brain. The enzymatic changes were more pronounced in the nonpregnant as compared with pregnant rats, in agreement with results of a previous study (Dobryszycka et al., 1974) in which several biochemical serum constituents were determined in rats treated in the same way with Epidian 5 or TETA. It should be emphasized that the analysis of acute phase factors (seromucoid, haptoglobin, sialic acid) and serum enzymes in the previous study showed different effects of the same toxic compound in pregnant and nonpregnant rats. A similar phenomenon occurred with tissue enzymes of rats rubbed with epoxy resin or stabilizer; AspAT activity was found to increase in the livers of nonpregnant rats and to decrease in pregnant ones, respectively. This observation is difficult to explain because AspAT activity in both control groups of pregnant and nonpregnant rats was similar. It is possible that the mechanisms leading to the difference may be only indirectly connected with pregnancy, and stem largely from disorders in the regulatory mechanism of sex hormones. According to Chen et al. (1973) administration of tetrachlorobiphenyls to male rats induced aniline hydroxylase and ethylmorphine N-demethylase activities, but in female rats decreased both enzyme systems. It seems possible that the different response of pregnant and nonpregnant rats to toxic compounds in the present experiments may have been due to endocrine factor accompanying pregnancy. Comparison of the influence of Epidian 5 and TETA on rats and guinea pigs (Dobryszycka et al., 1974; Woytori et al., 1974) subjected to dermal exposure has shown
26.14 !Z 1.66 14.88 + 0.57
150.00 + 12.47
AspAT AlAT
Achase
Liver
Brain
182.35 + 14.86
32.87 + 0.97” 21.44 + 1.05’
18.37 _+2.24’
Epidian 5 It= 10
a Average values of enzyme activities in units/g of wet tissue, +SD. b Results were analyzed statistically by Student’s f test. cp < 0.01. d0.05 > p > 0.01.
8.75 _+1.16
GGTP
Kidneys
n=lO
Enzymes”~ b
25.70 + 1.66 10.97 + 1.58 186.67 + 25.64
108.70 + 5.35”
8.45 zk 1.05
n=lO
38.67 + 0.68” 20.18 + 2.06’
12.06 + 1.28d
TETA n= 10
175.70 f. 15.07
19.25 & 1.16’ 11.76 + 1.41
12.93 + 1.13d
Epidian 5 n= 10
18.03 k 1.46’ 12.40 + 0.87
11.37 + 1.19
TETA n=lO
170.67 + 13.57
Pregnant rats rubbed with
AND AIAT) AND CHOLINESTERASE (Achase) AC~WIT~ESIN TISSUES OF RESIN EPIDIAN 5 OR TRIETHYLENETETRAMINE (TETA) STABILIZER
(AspAT EPOXY
Nonpregnant rats rubbed with
AMINOTRANSFERASES RATS TREATED WITH
Tissue
-
y-GLUTAMYLTRANSPEPTIDASE (GGTP), NONPREGNANT AND PREGNANT
TABLE I
E 2 Tz t!
2 B z
5
s!
10
WOYTOfi ET AL.
certain interesting relations. Biochemical examinations of serum components revealed a much stronger toxic effect of epoxy resin and stabilizer on pregnant guinea pigs and their fetuses than on rats. In sera of pregnant guinea pigs statistically significant changes were observed in total protein, seromucoid, sialic acid, and haptoglobin levels and in activities of lactate dehydrogenase, leucylnaphthylamidase, GGTP, aminotransferases, acid phosphatase, and cholinesterase, while in sera of nonpregnant guinea pigs changes were found in 3 out of 12 of these biochemical measures. In the course of the experiment 14 out of 22 guinea pigs died with degenerative changes of the placenta resulting in miscarriage or mortification of the fetus. On the other hand, the tissue enzymes, especially in nonpregnant rats, showed more numerous changes than those in nonpregnant guinea pigs. The fact that rats were rubbed with the compounds for 17 days, and guinea pigs, owing to longer duration of pregnancy, 65 days may have been significant. In spite of widely held opinion that pregnancy leads to greater sensitivity to toxic injury (Texler et al., 1970; Woyton et al., 1974) the results of our studies and those of Beliles (1972) seem to indicate that the toxic actions of certain compounds may be different in pregnant vs nonpregnant animals, depending on the species of animals employed. REFERENCES AMMER, D. (1970).Ocenaszkodliwegodzialania naskdreniektorych iywic syntetyzowanychw przemysle.Med. Pracy 21,7-14. BELILES, R. P. (1971).The influenceof pregnancyon the acutetoxicity of variouscompoundsin
mice. Toxicol. Appl. Pharmacol.23,537-W. CHEN, P. R., MEHENDALE, H. M. AND FISHBEIN, L. (1973).Effect of two isomerictetrachlorobiphenylson rats and their hepatic enzymes.Arch. Environ. Contam.Toxicol. 1, 36-47. DE LA HUERGA, J., YESINICK, C. AND POPPER, H. (1952).Calorimetric methodfor the determina-
tion of serumcholinesterase. J. Clin. Pathol. 22, 1126-l 133. DOBRYSZYCKA, W., WARWAS, M., WOYTOI+, A., WOYTOI+, J. AND SZACKI, J. (1974). Serum
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