Environmental Health Perspectives Vol. 57, pp. 75-84, 1984


# Experimental Studies on 

# Toxicity of 

# Ethylene Glycol Alkyl 

# Ethers in 

# Japan by Kasuke 

# Nagano,* Eiki 

# Nakayama,* Hisao 

# Oobayashi,* Tomoshi 

# Nishizawa,* Hirokazu 

# Okudat and 

# Kazunori Yamazaki*

Past studies onthe toxicological effects ofethylene glycol alkyl ethers aswell as therecentdataonthese chemicals inJapan are reviewed. Only a few researchers have participated in the study of ethylene glycol alkyl ethers in Japan. The effects of ethylene glycol alkyl ethers on testis and embryotoxic effects of ethylene glycol monomethyl ether (EGM) have been studied, as has the teratogenicity of ethylene glycol dimethyl ether (EGdM). Studies on ethylene glycol alkyl ethers and related compounds administered to mice by oral gavage revealed the occurrence of testicular atrophy and decreasedwhite blood cell count by EGM, EGdM, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether and ethylene glycol monoethyl etheracetate, andthetoxicitywasrelatedtotheirchemical structure. Onthe otherhand, ethylene glycol, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monophenyl ether, ethylene glycol monoacetate or ethylene glycol diacetate showed no such an effect. Studies on EGMusinghamsters orguineapigsrevealedthe occurrence oftesticularatrophysimilarto that observed in mice. In regard to the methyl ethers of other glycols, there is no convincing evidence that propylene glycol monomethyl ether, diethylene glycol monomethyl ether or diethylene glycol dimethyl ether causes testicular atrophy in mice. Teratological studies of EGM and EGdM revealed embryotoxic effects in mice. 

## Introduction In Japan, ethylene glycol ethers have been widely used as industrial solvents forresins, lacquers anddyes, but there are no available data on their use. The production of ethylene glycol ethers inJapan in 1980 is estimated tobe 43,048 tons (1). The total amount ofthe ethers imported in 1980 was reported to be 8,121 tons, 94.5% of which came from the U.S. (2). Only a few researchers have participated in studies on the toxicity of ethylene glycol ethers inJapan. Since 1976, we have studied the effects ofethylene glycol alkyl ethers onthe testis to define the possible relation between their chemical structures and the effects on the testis, and to elucidate the pathogenesis of testicular lesions (3). In addition, Uemura reported teratogenic effects of ethylene glycol dimethyl ether in mice in 1980 (4);

we also reported embryotoxic effects of ethylene glycol monomethyl ether in mice in 1981 (5). Past studies on
*Japan Bioassay Laboratory, Japan Industrial Safety and Health Association, 2445 Ohshibahara, Hirasawa, Hadano Kanagawa, 257 Japan. tOccupational Health Service Center, Japan Industrial Safety and Health Association, 35, Shiha 5-chome, Minato-ku, Tokyo; 108 Japan. 

### the 

### toxicological effects of ethylene 

### glycol alkyl ethers as 

### well as recent data on 

### these 

### chemicals in Japan are 

### reviewed in this paper. 

## Testicular Atrophy 

## Induced by 

## Ethylene 

## Glycol Alkyl Ethers Three experiments were conducted to evaluate the 

### toxicity of 

### ethylene glycol 

### alkyl ethers to 

### the testis: (1) 

### Testicular 

### changes in mice given 

### ethylene glycol alkyl 

### ethersandrelated

### compounds; (2) the effects

### of

### ethylene glycol monomethyl ether on 

### the testis of hamsters 

### and 

### guinea pigs; (3) The effects of 

### alkyl ethers of other 

### glycols on 

### the testis of mice. We 

### attempted to 

### determine the 

### possible relation 

### betweentheirchemical structures 

### andthe 

### effects onthe 

### testis, and the 

### pathogenesis of 

### testicular lesions in 

### these 

### experiments. 

### Testicular 

### Changes in 

### Mice 

### Given 

### Ethylene Glycol Alkyl Ethers and 

### Related 

### Compounds Materials

### andMethods. Male

### JCL-ICRmice 

### (Japan 

### CLEA 

### Co.), 6 

### weeks of age, were 

### used. The materialsNAGANO ETAL.

0,8

0- ae

(U

L. 0

.0

m 0,

D :0 0 -
%._

4._ n

FIGURE 1. Testicular atrophy induced by EGM. Dose-dependent decrease in testis size is shown. 

### tested were 

### ethylene glycol 

### (E monomethyl ether 

### (EGM), 

### ethyle ether 

### (EGE), ethylene

### glycolmono 

### ethylene 

### glycolmonobutyl ether 

### (E monophenyl ether 

### (EGPh), 

### ethyler etheracetate 

### (EGMA), ethylene

### gi acetate 

### (EGEA), 

### ethylene 

### glycol ethylene 

### glycol diacetate 

### (EGdA) dimethylether 

### (EGdM). EGPrand 

### from

### TokyoKasei

### Kogyo

### Co., EGA Co. and the rest 

### from Wako 

### Cher

CH27OH CH2-OH (EG)

CH2-0-CH3 CH2-O-C2H5 CH2-O-C3H7 ICI H I CH270H CH270H CH270H

(EGE) (EGPr)
CH27OH

CH2-OOC (EGA) (EGEA) 

### ,G), 

### ethylene glycol

ne glycol 

### monoethyl 

### opropyl ether 

### (EGPr), ;GB), ethylene

### glycol no 041r"Al mnnmamthulr Daily dose (mg/kg) FIGURE 2. Relation between daily doses (expressed as mg/kg body weight) andtestisweight ofmicewhichwere treatedwithethylene glycolalkyl ethers andrelatedcompounds: (h-[ ) EG; (o-o) EGM; (-@*) EGE; (A---A) EGPr; (A-A) EGB; (A-A) EGPh; (o---o) EGMA; (A---e) EGEA; (U---.) EGA; (u--_) EGdA; (o---o) EGdM. Testis body weight ratio are expressed as the mean of the values from five mice at each dose. ka IIIVU 

### £WRlulAllylAJ Gastric intubationwas employed for administration of 

### Lycolmonoethyl ether 

### each

## materialbecause ofthe

### necessityof

### administering monoacetate 

### (EGA), accurate 

### amount of

### materials. Each ofthe 

### samples was 

## Iand ethylene glycol diluted 

### with 

### water or 

### olive oil and 

### given orally by EGdAwere obtained 

### stomach tube 5 

### days per week for 5 

### weeks. The daily fromKanto Chemical 

### doseswere4000, 2000, 1000 and500mg/kgbody

### weight mical Co. 

### for 

### EG, EGE and 

### EGEA; 2000, 1000, 500, 250, 125 and

62.5 

### mg/kg body 

### weight for EGM and 

### EGMA; 2000, 1000 

### and 500 

### mg/kgbodyweight for EGPr, 

### EGB, EGA and 

### EGdA; 1000, 500 and 250 mg/kg 

### body weight for 

### EGdM. The 

### control mice were givenwaterby 

### the same 

## CH2-O-C4H9 

## CH2-OC,H5 method. Onthe

## followingdayofthefinal

### administration, 12 1 

### animals were 

### necropsied under 

### pentobarbital sodium 

### CH2-OH CH2-OH 

### anesthesia. 

### The 

### testes were 

### weighed and the 

### combined (EGB) (EGPh) 

### weight of 

### seminal vesicles and 

### coagulating gland was

also measured. Tissue 

### specimens for 

### histopathological 

### CH2-OOCCH3 examination were 

### fixed in 

### 10% buffered formalin XH3 

### CH2-OOCCH3 solution, 

### embedded in 

### paraffin, sectioned, and 

### stained (EGdA) with 

### hematoxylin and 

### eosin. Blood for 

### hematological

studies was taken from the 

### posterior vena 

### cava at the time of 

### necropsy. 

### Results. Gross observation showed that the testes 

### of mice 

### given some 

### of the 

### ethylene 

### glycol alkyl ethers 0,6

0,4

0,2

I I I a I

. p 62,5 125 250 500 1000 2000 4000

(EGM)

CH2-O-CH3 CH2-O-C2H5 CH2-OOCCH3 CH2-0OCCH3 (EGMA)

CH2-O-CH3 CH2-0-CH3 (EGdM) L 76

-ETHYLENE GLYCOL ALKYL ETHERS TOXICITY



### were 

### decreased in

### size 

### (Fig. 1). The

### weight ofthe 

### testes (expressed as 

### testis-body weight 

### ratio) of 

### mice 

### administered ethylene glycol alkyl ethers or 

### related 

### compounds for 

### 5 weeks is 

### shownin

### Figure 2. In

### animals

0,8

-

0,6 

## F

0,4 r

0,2 F

0,5 1 5 10

Daily dose (m mol/kg) FIGURE 3. Relation between daily doses (mmole/kg body weight) and testis weight ofmice which were treated with ethylene glycol alkyl ethers and related compounds. Symbols as in Fig. 2. 

### given EGM, EGE, EGMA, EGEA and 

### EGdM, dose

### dependentdecreasesin

### testicular

### weightwere

### observed. 

### Considering toxic 

### effects on 

### the testis based on 

### testicular 

### weight and 

### daily dose, as 

### weight per 

### body weight, EGM seemed to 

### be most 

### toxic, followed 

### by EGdM, EGMA, EGE and 

### EGEA, in that order. 

### Esterification appeared to 

### lessen the 

### testicular 

### atrophy effect in 

### both the 

### methyl and 

### ethyl ethers of 

### ethylene glycol, and 

### dimethyl ethers had such 

### toxicity less than 

### monomethyl ethers. 

### Examination of 

### the testicular 

### weight and 

### daily molar 

### dose 

### per body weight (Fig. 

### 3) showed that testicular 

### atrophy was 

### greater for 

### EGM, EGMA and EGdM than for 

### EGE and 

### EGMA. The 

### reduction in 

### testicular toxicity by 

### esterification or 

### dimethylationwhen

### dailydosewas 

### expressedas

### weight per

### bodyweight was 

### due to 

### the difference in

### molecular 

### weight of 

### these 

### compounds. No 

### significant difference in 

### weight of the 

### testis was 

### foundin

### EG, EGPr, EGB, EGPh, EGAor

### EGdAgroups as 

### compared with 

### that of control animals. A 

### slight decrease inthe combined

### weight ofthe seminal vesicles 

### and the 

### coagulating gland was seen 

### only in 

### groups receiving higher doses of 

### EGM, EGMA and EGdM. 

### Histopathological examinations of 

### the testis from 

### mice 

### given EGM, EGE, EGMA, EGEA and EGdM 

### revealed 

### dose-related atrophy of 

### the 

### seminiferous epithelium at 

### various degrees. Sertoli cells remained normal 

### up to 

### later stage. 

### Leydig cells were normal in 

### appearance, though 

### infrequently proliferative 

### (Fig. 4-13). In 

### the 

### hematological examination, the decrease 

### in 

### white 

### bloodcellwas 

### themost

### prominent 

### change. 

### EGM, EGE, 

### EGMA. EGEA and 

### EGdM caused a 

### significant decreaseinwhitebloodcellcount, andtheorderoftoxic

ZL '. ,, ,*

M 

### -M

S>;* *X -s.

FIGURE 4. Testis of control mouse. H&E. - e

0- 0

._

C D 0

0 4._

0 I- 77NAGANO ET AL.

FIGURE 5. Testis of mouse treated with 2000 mg/kg/day of EGM. Seminiferous tubules are decreased in size and irregularly shaped. Spermiogenic cells have disappeared completely. H&E.

FIGURE 6. Testis ofmouse treatedwith 1000mg/kg/dayofEGM. Small tubuleswithdisappearance ofspermiogenic cell cells are shown. H&E.



### effect on 

### leukocyte by these chemicals resembled that on 

### testicular

### weight (Fig. 14). The 

### change in 

### red blood cells was 

### slighter than 

### leukocyte 

### changes, and red cell count, 

### packed cell volume 

### and/or 

### hemoglobin content 

### decreased at 

### the 

### higher dose levels of 

### EGM, 

### EGMA, EGEA and 

### EGdM. For 

### EGB-treated mice, a 

### decrease in 

### red cell count was 

### noted in 500 

### mg/kg or 

### higher dose 

### groups. 

### Effects of 

### Ethylene Glycol 

### Monomethyl Ether on 

### Testis of Hamsters and 

### Guinea 

## Pigs Since the 

### effect of

### ethylene 

### glycol 

### alkyl ethers on 

### the testis ofother

### animal 

### species was not

### known, we 

### carried out 

### preliminary studies 

### of the toxic 

### effect of EGM on 

### the testis of hamsters 

### and 

### guinea 

### pigs. 78ETHYLENE GLYCOL ALKYL ETHERS TOXICITY

FIGURE 7. Same testis as in Fig. 6. Sertoli cells (A) and spermatogonia (B) are shown in the basal layer. H&E.

FIGURE 8. Testis ofmouse treatedwith 500mg/kg/dayofEGM. Some spermatogonia (A) and spermatocytes (B) arepreserved. Leydigcells (C) are proliferative. H&E. 

### Materials andMethods. 

### Adult male 

### Syrian golden hamsters and

### guineapigs were 

### used. 

### EGM was 

### diluted with water, 

### and 

### given 

### orally with 

### stomach tube 5 

### days per 

### week for 5 

### weeks. 

### The 

### daily doses were 

### 500, 250, 125 

### and 62.5 

### mg/kgbody

### weight for

### hamsters, and 500 

### and 250

### mg/kgfor

### guinea

### pigs. The 

### control

### animals were 

### given water 

### by the same 

### method. On the 

### following day of the 

### final 

### administration, animals were 

### necropsied under

### pentobarbital sodiumanesthesia. The testeswere 

### weighed and the combined 

### weight of the 

### seminal vesicles and 

### coagulating gland was 

### also measured. Blood for white 

### blood cell count was 

### taken from the 

### posterior vena cava at 

### the time 

### of necropsy. 

### Results. Adecrease in

### testicular

### weightwas seenin 

### all dose groups 

### of hamsters (500, 

### 250, 125 

### and 62.5 

### mg/kgbodyweight group), while neither 

### the combined 

### weight ofthe seminalvesicles 

### and

### coagulating

### glandnor 

### white blood cell count was 

### affected 

### (Table 1). 79NAGANO ET AL.

FIGURE 9. Testis of mouse treated with 250 mg/kg/day of EGM. Some tubules contain spermatozoa (A), but other tubules are atrophic (B). H&E.

FIGURE 10. Testis of mouse treated with 1000 mg/kg/day of EGMA. Sertoli cells and a few spermatogonia are shown. H&E.
Table 1. Effects of ethylene glycol monomethyl ether on hamsters.
Mean seminal vesicle and Daily dose, No. animals/ Mean body Mean testis weight coagulating gland weight Mean WBC/ mg/kg group weight, g mg %a mg %a mm3 500 4 112 652t 0.58t 1172 1.03 4000 250 4 121 748t 0.62t 1543 1.29 4762 125 4 124 1299t 1.06t 1643 1.33 4675 62.5 4 131 3559 2.63* 1795 1.38 5433 Control 4 131 3715 2.84 1769 1.36 4925 

### aOrgan/body weight ratio. *Significantly different (p < 0.05) from the control group. tSignificantly different (p < 0.01) from the control group. 80ETHYLENE GLYCOL ALKYL ETHERS TOXICITY

FIGURE 11. Testis of mouse treated with 1000 mg/kg/day of EGdM. Spermiogenic cells have disappeared. H&E.

FIGURE 12. Testis of mouse treated with 2000 mg/kg/day of EGE. Some spermiogenic cells are preserved. H&E.

Table 2. Effects of ethylene glycol monomethyl ether on guinea pigs.a
Mean seminal vesicle and Daily dose, No. animals/ Mean body Mean testis weight coagulating gland weight Mean WBC/ mg/kg group weight, g mg %a mg %b mm3 500 3 782 927 0.12 4109 0.525 4000 250 3 755 946 0.13 3635 0.481 4100 Control 3 749 3889 0.52 3883 0.518 9180 aStatistical examination was not carried out. 

### bOrgan/body weight ratio. 81NAGANO ET AL.

FIGURE 13. Testis of mouse treated with 4000 mg/kg/day of EGMA. Sertoli cells and some spermatogonia are preserved. H&E.

5000

4000

E E "I

0

0 0 0

.0 la 3000

_

2000

_

1000 EGM

62,5 125 250 500 1000 2000 4000

Daily dose (mg/kg)

FIGURE 14. Relation between daily dose (expressed as mg/kg body weight) andwhiteblood cell count ofmicewhich were treatedwith ethyleneglycolalkylethersandrelatedcompounds.(G-o); EGM; (o-o) EGE; (o---o) EGMA; ( ---e) EGEA; (o---o) EGdM. Whitebloodcell count is expressed as the mean ofthe values from five mice at each daily dose. The 

### testicularweight inalldose 

### groups of

### guineapigs (500 

### and 250 

### mg/kg) 

### decreased to 

### one-fourth of that in 

### the 

### control group, while the 

### combinedweight of

### seminal vesicles and 

### coagulating gland was not 

### affected. White 

### blood cell count in 

### all dose groups was 

### decreased to 

### one-half of that in 

### the 

### control group 

### (Thble 2). From these 

### results, it 

### appears that oral 

### administration of 

### EGM causes 

### testicular atrophy in hamsters 

### and guinea pigs in 

### the same manner as 

### observed in mice.


### Effects 

### of 

### Alkyl Ethers of Other 

### Glycols on 

### the Testis of Mice Some

### alkyl ethers of

### ethylene

### glycols induce

### testicular 

### atrophy in some 

### animal 

### species. In this 

### experiment, we 

### describe the 

### possible effect of the 

### methyl ether of 

### propylene and 

### diethylene glycol on 

### the testis. 

### Materialsand

### Methods. Male

### JCL-ICRmice 

### (Japan 

### CLEA 

### Co.), 6 

### weeks 

### of age, were 

### used. The 

### materials used were 

### propylene glycol monomethyl ether 

### (PGM), diethylene 

### glycol monomethyl ether 

### (dEGM) and di

### ethylene 

### glycol dimethyl ether 

### (dEGdM), and 

### EGM and 

### EGE, as 

### positive control. PGM was 

### obtained from Tokyo 

### Kasei Kogyo 

### Co., andother

### chemicals from

### Wako 

### Chemical Co. 

### PGM, dEGM and 

### dEGdM were ad

### ministered tomice 

### for 25 

### days in

### the

### drinkingwater at a 

### level of 2% 

### and EGM 

### and EGE for 18 

### days at a 

### level of 2.5%. 

### Control mice were 

### allowed water ad 

### libitum. Animalswere

### necropsiedunder

### pentobarbitalanesthesia at the end of 

### administration. Testicular 

### weight and the 

### combined 

### weight of 

### seminal vesicles 

### and 

### coagulating gland were 

### measured. Blood for white 

### blood cell count was 

### taken from the 

### posterior vena 

### cava at 

### the time of necropsy. 82ETHYLENE GLYCOL ALKYL ETHERS TOXICITY

Table 3. Effects of alkyl ethers of other glycols on mice.
Mean seminal vesicle and Concen- Duration of No. animals/ Mean body Mean testis weight coagulating gland weight Mean WBC/ Compound tration, %a dosing, days group weight, g mg gb %b mm3 PGM 2.0 25 5 41.2 322 0.78 397 0.97 4530 dEGM 2.0 25 5 38.6 237 0.62 420 1.09 4690 dEGdM 2.0 25 4 41.0 218 0.53 381 0.93 3934 Control 0 25 5 40.6 290 0.71 441 1.09 3270 EGM 2.5 18 8 26.2t 47t 0.18k 191t 0.72 538t EGE 2.5 18 8 33.7* 122t 0.36t 260 0.77 1506 Control 0 18 4 39.0 221 0.57 242 0.62 1740 a% in

### drinking water. bOrgan/body weight ratio. *Significantly different (p < 0.05) from the control group. tSignificantly different (p < 0.01) from the control group.


### Results. No 

### significant difference was 

### noted between 

### PGM-, dEGM- or 

### dEGdM-treated groups 

### and control 

### (inthetesticular

### weight, the combined

### weight of 

### seminal vesicles and 

### coagulating gland or 

### white blood 

### cell 

### count). In 

### dEGM and 

### dEGdM groups, a 

### slight decrease in 

### testicular 

### weight was 

### observed, but these 

### decreases were 

### due to one 

### animal ofeachgroup 

### and are 

### statistically not 

### significant. 

### However, a 

### decrease in 

### testicular 

### weight and/or 

### white blood cell count was 

### observedin

### both

### EGM-andEGE-treatedgroups. 

### Under these 

### experimental 

### conditions, we cannot 

### indicate that PGM, dEGM or 

### dEGdM causes any 

### testicular atrophy (Table 3). 

## Embryotoxic Effects of 

## Ethylene 

## Glycol Monomethyl Ether and 

## Ethylene 

## Glycol Dimethyl Ether in 

## Mice It 

### is well known that 

### alkylating agents 

### such as 

### Busulphan inhibit cell

### proliferation and cause 

### testicular 

### atrophy and 

### leukopenia. These chemicals 

### produce a 

### lethal effect or

### damage to 

### the fetuses 

### (6). The 

### effects of 

### ethylene 

### glycol alkyl ethers on 

### testis and 

### leukocyte resembled those of 

### alkylating agents. 

### Consequently, 

### ethylene 

### glycol alkyl ethers which cause 

### testicular 

### atrophy and 

### leukopenia may 

### have also 

### embryotoxic effects. We 

### studied the 

### embryotoxic effects of 

### EGM, and Uemura 

### studied those 

### of 

### EGdM. These studies are 

### summarized here. 

### Materials and Methods Ethylene 

### Glycol Monomethyl Ether 

### (EGM). Fe

### male 

### JCL-ICR mice 

### (Japan CLEA 

### Co.) were 

### housed 

### overnight withmales of

### the same 

### stock, and the 

### day on 

### whicha

### vaginalplugwas 

### observedwas

### designatedday0 

### of 

### gestation. On 

### days 7 to 14 

### of 

### gestation, EGM at 

### various 

### daily doses 

### (1000, 

### 500, 250, 125, 62.5 

### and 31.25 mg/kg body weight) dissolved in water was given 

### by gastric intubation. The group 

### administered vehicle 

### only servedas 

### the control. On

### day 18 of

### gestation, mice were 

### sacrificed. Litter 

### values and gross 

### abnormalities were 

### recorded. 

### Blood was 

### taken from dams for white blood cell count. 

### Living 

### fetuses with no 

### external malformations orwithonly

### abnormaldigitswere 

### examinedfor 

### skeletal abnormalities and the 

### degree of ossification. 

### Ethylene

### GlycolDimethylEther 

### (EGdM). Female CRJ:CD-1 mice 

### (Charles River

### Japan 

### Inc., 12 weeks of 

### age) were 

### housed 

### overnight with same 

### stock males (14 weeks ofage), and the 

### day on

### which a

### vaginal plugwas 

### observed was 

### designated day 0 

### of

### gestation. On 

### days 7 to 10 

### of 

### gestation, 

### EGdM at 

### various 

### daily doses (490, 350 

### and 250 

### mg/kg

### bodyweight) 

### dissolved inwaterwas given 

### by gastric 

### intutabion. The group 

### administered 

### vehicle only served as 

### the 

### control. 

### On day 18 

### of 

### gestation, mice were 

### sacrificed. Littervalues and gross 

### abnormalities were 

### examined. Fetuses were 

### examined for 

### their skeletal abnormalities and the 

### degree of 

### ossification. 

### Results EGM. All 

### fetuses except one 

### of the 500 

### mg/kg group were 

### dead in 

### the 1000 

### and 500 

### mg/kg group, 

### and 

### therewas an

### increase in

### the incidence ofdead fetuses in 

### the 250 

### mg/kg group. 

### Gross 

### abnormalities, such as 

### Although the 

### significant 

### maternal toxicity was not 

### observed, both 

### EGM and 

### EGdM induced marked and 

### dose-related 

### embryotoxic effects. A summary 

### of the results is 

### given in 

### Figure 15. 

### exencephaly, umbilical 

### hernia or 

### abnormal 

### digits, were 

### observed in the 250 

### mg/kg group. 

### Reduction in 

### fetal 

### weight was seen in 

### the 125 

### mg/kg and 

### higher dose groups. 

### Skeletal malformations 

### including fusion 

### and agenesis of either ribs or 

### vertebrae were 

### observed in 62.5 

### mg/kg or 

### higher dose groups. 

### Skeletal variations such as 

### bifurcated or 

### split cervical vertebrae and 

### retardationof

### skeletal ossification in

### fetuses were 

### noted in 

### all treated groups 

### (250-31.25 mg/kg). 8384 NAGANO ET AL.

EON Leucopenla of dams Fetal death Gross anomiles Fetal body weight loss Skeletal malformations Skeletal variations Retardation of ossification
31,25 62,5 125 250 500 1000 Daily dose of EGO (mg/kg)

EGdS Fetal death Gross anomalies Fetal body Welght loss Skeletal malformations Skeletal variations Retardation of ossification 250 350 490 Daily dose of E1dM (mg/kg)
FIGURE 15. Summary of study on embryotoxic effects of EGM and EGdM.


### EGdM. There was an 

### increase in 

### the incidence of dead fetuses in 

### the 490 

### mg/kg group. An 

### increase in number of 

### gross abnormalities, such 

### as exencephaly, caudaldefectandumbilical

### hernia, were 

### observedin

### the 350 

### mg/kg 

### and higher dose groups. In 

### all treated groups, 

### increased incidence of skeletal malformations such as fused ribs and vertebrae, 

### skeletal 

### variations suchas extra

### ribs and

### retardationofskeletalossification was 

### noted. 

### Discussion Past studies and 

### recent data on 

### the toxicological effects of

### ethyleneglycolethers in

### Japanwere

### reviewed. 

### Testicular 

### atrophy in 

### mice, hamsters 

### and guinea pigs were observed on 

### administration of some 

### ethylene glycol alkyl 

### ethers, i.e., 

### EGM, EGE, 

### EGMA, EGEA and 

### EGdM. A 

### correlation 

### between 

### chemical structures and their 

### effects on 

### testis was 

### observed. Testicular atrophy was induced by EGM, 

### EGE, 

### EGMA, EGEA and 

### EGdM, and the 

### atrophy was 

### greater 

### for 

### EGM, EGMA and 

### EGdM than 

### EGE and 

### EGEA, when dose level is expressed as 

### mole/body 

### weight. However, no 

### significant effect on 

### the testis was seen in 

### the groups treatedwith

### EG, EGPr, EGB, EGPh, 

### EGAand 

### EGdA. Alkyl ethers of 

### other glycols, i.e., 

### PGM, dEGM and 

### dEGdM, did not 

### show 

### any 

### significant evidence on 

### the 

### induction of 

### testicular atrophy in 

### mice. From the 

### above findings it can be concluded that there is 

### a 

### correlation between 

### chemical structures 

### of 

### ethylene glycol 

### alkyl ethers and 

### their 

### ability to induce testicular 

### atrophy. Both 

### methyl and 

### ethyl ethers of 

### ethylene glycols cause 

### testicular

### atrophy. Methyl ethers have agreater effect thanethyl ethers. Esterification of 

### these 

### chemicals does not affect the potency 

### of the 

### toxicity. Dimethyl ethers of 

### ethylene glycols have 

### quantitatively the same 

### testicular 

### toxicity as mono

### methyl ethers. 

### Alkyl ethers of 

### other 

### glycols such as propyleneglycolanddiethyleneglycolhavenosignificant 

### effect on 

### the testis. Ethylene glycol alkyl ethers can be 

### concluded to induce testicular atrophy by affecting dividing cells 

### of some 

### kinds and inhibiting 

### cell proliferation from the 

### following reasons. 

### Alkylating agents 

### induce leukopenia as 

### well as 

### testicular 

### atrophy by affecting cell division 

### (7). 

### Similarly, EGM, EGE, EGMA, EGEA and EGdM cause 

### leukopenia at 

### the same 

### degree as 

### for 

### testicular 

### atrophy. However, 

### histopathologically, Leydig cells and 

### Sertoli cellswere 

### foundto

### benormal evenat

### higherdose levels. Onlya

### slightdecrease inweightwas 

### recorded for the seminal vesicle and the 

### coagulating 

### gland at 

### extremely higher dose levels. 

### By these 

### findings, tes

### ticular 

### changes induced 

### by ethylene glycol 

### alkyl ethers can 

### be 

### distinguished from those 

### induced 

### by hormonal substances (e.g., 17 

### 3-estradiol) or 

### vasoactive substances (e.g., 

### cadmium 

### chloride) (8). 

### Substances showing 

### inhibitory effect on 

### cell proliferation are 

### known to 

### produce a 

### lethal effect on or 

### damage to 

### the fetus 

### when given to pregnant 

### animals (6). 

### EGM and EGdM exhibit marked embryotoxic 

### effects. This fact also supports 

### the conclusion that 

### ethylene glycol alkyl ethers have an 

### inhibitory effect on 

### cell 

### proliferation. From 

### the results ofthe present 

### animal 

### experiments, it can 

### be concluded 

### that some 

### ethylene 

### glycol alkyl ethers 

### have toxic 

### effects on 

### the testis and 

### fetus.

The authors are indebted to Dr. M. Enomoto, Dr. K. Uemura, Mr. Y. Koshima and Mr. Y. Kurakata for help in the presentation of this paper and many useful suggestions for its improvement.

REFERENCES 1. Ministry of International Trade and Industry. Year Book of Chemical Industrial Statistics, Research Institute ofInternational Trade and Industry, Tokyo, 1981. 2. Japan TariffAssociation. Japan Export and Import. Japan Tariff Association, Tokyo, 1981. 3. Nagano, K., Nakayama, E., Koyano, M., Oobayashi, H., Adachi, H., andYamada, T. Testicularatrophyofmice inducedbyethylene glycol mono alkyl ethers. Japan. J. Ind. Health 21: 29-35 (1979). 4. Uemura, K. The teratogenic effects of ethylene glycol dimethyl ether on mouse. Acta Obst. Gynaec. Japan. 32: 113-121 (1980). 5. Nagano, K., Nakayama, E., Oobayashi, H., Yamada, T., Adachi, H., Nishizawa, T., Ozawa, H., Nakaichi, M., Okuda, H., Minami, K., and Yamazaki, K. Embryotoxic effects of ethylene glycol monomethyl ether in mice. Toxicology 20: 335-343 (1981). 6. Hemsworth, B. N., and Jackson, H. Embryopathies induced by cytotoxic substances. In: A Symposium on Embryopathic Activity of Drugs (J. M. Robson, Ed.), Churchill, London, 1965, pp. 116-137. 7. Patanelli, D. J. Suppression of fertility in the male. In: Endocrinology, Vol. 5 (R. 0. Greep and E. B. Astwood, Eds.), American Physiological Society, Washington, DC, 1975. 8. Zshauer, A., and Hodel, C. Drug-induced histological changes in rat seminiferous tubular epithelium. Arch. Ibxicol. (Suppl.) 4: 466-470 (1980).