Number Of Abnormal Spermatozoa Research Articles

Phytoestrogen treatment induces testis alterations in dogs. Potential use in population control

Dog overpopulation is considered a human health risk; they are the terrestrial vector of rabies and reservoirs for other human diseases. Surgical neutering and intratesticular injections have been used in male dogs. Physiological and morphological alterations in reproductive organs can be induced by phytoestrogens. Our goal was to evaluate the effect of oral coumestrol on dog ejaculates and testis histology. Two groups of 5 healthy adult dogs were used. One coumestrolcontaining biscuit was given once a week for a 4 week period to the experimental group. Ejaculates were obtained and evaluated. After treatment, testis were obtained and processed for histology. Compared to controls, treated dogs have reduced tubules (462 +/- 1.4 vs 336 +/- 2 micron(2)), spermatogenic epithelium (49.1 +/- 0.01 vs 13.3 +/- 0.01 micron(2)), and lumen opening (891 +/- 1.4 vs 530 +/- 26.9 micron). Ejaculates from treated animals have increased numbers of abnormal spermatozoa and reduced sperm concentration.

Essential fatty acid deficiency induces fatty acid desaturase expression in rat epididymis, but not in testis

On the molecular level, essential fatty acid deficiency (EFAD) has been associated with induced fatty acid (FA) desaturase expression and activity in several tissues. However, there seem to be exceptions. In the present study, we examine the effects of EFAD in the male rat genital tract, combining FA analysis, gene expression studies, and morphological evaluation of epididymal spermatozoa. When feeding 21-day-old Wistar rats, a fat-free diet for 6 weeks, an increase in 18:1n-9 and 20:3n-9 and a concomitant decrease in the 18:2n-6 and 20:4n-6 species are seen in testis, as well as in liver. However, with regard to desaturase expression the rat testis seems to be unresponsive to EFAD conditions, in contrast to other organs studied. In the sexually mature testis none of the desaturases (SCD1, SCD2, D5D, or D6D) are induced in response to lowered contents of polyunsaturated FAs. This also applies to caput epididymis, while EFAD sensitivity is regained in cauda epididymis, where the desaturases are upregulated. The FA profile of epididymal spermatozoa is increasingly affected by EFAD during the transport from testis to cauda epididymis. Furthermore, a significant increase in the number of abnormal spermatozoa is observed in cauda epididymis.

Comprehensive assessment of the effect of Sphenocentrum jollyanum root extract on male reproductive activity in albino rats.

Aim: To evaluate the effect of methanol extract from the Sphenocentrum jollyanum root on male reproductive activity. Methods: Male albino rats were treated orally with distilled water (vehicle for the extract; control) and 50, 100 and 150 mgkg-1 body weight of Sphenocentrum jollyanum root extract for 8weeks. Each group had its own recovery. Rats were killed 24h after the last treatment. Caudal epididymal sperm count, motility, viability, morphology and organ weights were determined. Hematological indices, serum proteins, enzymes, testicular superoxide dismutase (SOD) activity, and testicular and epididymal histology were determined. Results: Compared with the control, the extract caused a dose dependent significant (P<0.05) reduction in progressive motility of spermatozoa, viability and total sperm counts. The number of abnormal spermatozoa and epididymal volume were not statistically significant. There was a significant increase (P<0.05) in serum testosterone levels in rats treated with 50 (P<0.01) and 100mgkg-1 (P<0.05) of Sphenocentrum jollyanum. There was a significant (P<0.05) increase in red blood cell count, packed cell volume and hemoglobin concentration, whereas there was no change in white blood cell count, mean total serum protein, albumin and globulin in the sera of Sphenocentrum jollyanum treated rats when compared with the control. The extract caused a significant decrease (P<0.05) in serum aspartate and alanine aminotransferase activities with a significant increase (P<0.05) in testicular SOD activity at a dose of 50mgkg-1 bodyweight. Testicular cytoarchitecture of the extract treated rats showed degeneration of seminiferous tubules, whereas regeneration of germinal epithelium and restructuring of the germinal interstitium occurred in the recovery rats. No lesions were observed in the epididymis of the rats. Conclusion: The results suggest that methanol extract of the Sphenocentrum jollyanum root could produce harmful effects on reproductive functions in male albino rats which can be attributed to poor sperm quantity (epididymal sperm count), quality (sperm motility, viability and morphology) and testicular degeneration. The steroidogenic potential of the plant could explain its use as an aphrodisiac agent. (Reprod Med Biol 2006; 5: 283-292).

5-Aminosalicylic acid reverses endosulfan-induced testicular toxicity in male rats

Pre-treatment with 5-aminosalicylic acid (5-ASA) significantly reduced sperm-shape abnormalities in endosulfan-treated rats. The number of abnormal sperm in the epididymis was markedly increased by endosulfan treatment but pre-treatment with 5-ASA kept these values close to normal. Treatment with 5-ASA at a dose of 25 mg/kg bw was more effective in reducing sperm-shape abnormality and sperm count than at a dose of 50 mg/kg bw. Endosulfan significantly increased the level of lactate dehydrogenase (LDH) in rats but a marked decrease was observed upon pre-treatment with 25 mg/kg bw 5-ASA. Changes in plasma testosterone levels were not significantly correlated with 5-ASA pre-treatment but histopathological analysis of seminiferous tubules and Leydig cells showed significant protection from endosulfan-induced tissue damage such as necrosis. The population of Sertoli cells increased and the lumen of the seminiferous tubules contained a greater number of spermatids. There was a corresponding increase in the number of Leydig cells. A curative study with 5-ASA showed a similar protection from endosulfan-induced toxicity and cellular damage, but the extent of protection was significantly lower.

The effects of dietary vitamin B12 deficiency on sperm maturation in developing and growing male rats.

To evaluate the role of vitamin B12 on spermatogenesis, the effects of dietary vitamin B12 deficiency on sperm maturation in developing rat fetuses and young growing rats were examined. The vitamin B12-deficient diet was given to all the animals for three different periods: whole period (gestation to mature), gestation period (gestation to weaning), or immature period (3-12 weeks postnatal). Sperm examination revealed that the sperm count was markedly lower in male progeny (F1) that were vitamin B12-deficient during the whole period. In addition, a significantly higher number of abnormal sperm, such as tailless and amorphous sperm, was observed. In male rats that were vitamin B12-deficient during the immature period, the incidence of abnormal sperms was 14.4% and 4.8% for tailless and short tail, respectively. The motion rates, such as path velocity and straight line velocity, were decreased to 20-40% of the control value in rats that were vitamin B12-deficient both during the whole and gestation periods. However, no effects of vitamin B12 deficiency on sperm motility were observed during the immature and mature periods. From these findings, we suggest that dietary vitamin B12 deficiency during pregnancy may induce irreversible damage in the germ cells of embryos and affect the maturation of spermatozoa.

The effects of dietary vitamin B12 deficiency on sperm maturation in developing and growing male rats

To evaluate the role of vitamin B12 on spermatogenesis, the effects of dietary vitamin B12 deficiency on sperm maturation in developing rat fetuses and young growing rats were examined. The vitamin B12-deficient diet was given to all the animals for three different periods: whole period (gestation to mature), gestation period (gestation to weaning), or immature period (3-12 weeks postnatal). Sperm examination revealed that the sperm count was markedly lower in male progeny (F1) that were vitamin B12-deficient during the whole period. In addition, a significantly higher number of abnormal sperm, such as tailless and amorphous sperm, was observed. In male rats that were vitamin B12-deficient during the immature period, the incidence of abnormal sperms was 14.4% and 4.8% for tailless and short tail, respectively. The motion rates, such as path velocity and straight line velocity, were decreased to 20-40% of the control value in rats that were vitamin B12-deficient both during the whole and gestation periods. However, no effects of vitamin B12 deficiency on sperm motility were observed during the immature and mature periods. From these findings, we suggest that dietary vitamin B12 deficiency during pregnancy may induce irreversible damage in the germ cells of embryos and affect the maturation of spermatozoa.

Time to pregnancy and semen parameters: a cross-sectional study among fertile couples from four European cities.

In fertile populations, little is known about the association between semen parameters and time to pregnancy (TTP). Pregnant women from Copenhagen, Edinburgh, Paris and Turku who conceived without medical intervention were asked for their TTP (942 couples), and their partners provided a semen sample. The proportion of morphologically normal sperm and the multiple anomalies index (MAI, ratio of the total number of anomalies to the number of abnormal sperm) were centrally estimated. We estimated rate ratios for the occurrence of a pregnancy by a discrete survival model, adjusted for sexual activity and female factors affecting fecundity. Increasing sperm concentration influenced TTP up to 55 x 10(6)/ml. The proportion of morphologically normal sperm influenced TTP up to 39% according to David's criteria, and this association held among the subjects with a sperm concentration >55 x 10(6)/ml. For strict criteria, the threshold value was 19% normal sperm. An increase of 0.5 in MAI was associated with an adjusted rate ratio for the occurrence of a pregnancy of 0.68 (95% confidence interval: 0.54-0.85). These results highlight the importance of sperm morphology parameters and indicate that the effect of proportion of normal sperm on TTP may be independent of sperm concentration.

The effect of the aqueous extract of Cynomorium coccineum on the epididymal sperm pattern of the rat.

An aqueous extract of Cynomorium coccineum was administered by stomach tube to ten mature male Wistar rats, at a dose of 47 mg/100 kg body weight/day for 14 consecutive days. Ten rats were kept as controls and received normal saline by oral route at the same dosing interval. Sperm was collected from the epididymes after decapitation. The results revealed that the water extract of the Cynomorium coccineum induced significant increase in the sperm count, improved the percentage of live sperm and their motility and decreased the number of abnormal sperm. Testicular histology showed increased spermatogenesis and seminiferous tubules full of sperm in the treated group compared with the controls.

Oligoasthenozoospermia is not associated with spontaneous abortions following in vivo pregnancies contrasting with in vitro fertilization data.

Previous data showed an association between low motile density (< 10 million motile/mL) and spontaneous abortion (SAB) following in vitro fertilization-embryo transfer (IVF-ET). The purpose of this study was to determine if the same association existed following intrauterine insemination (IUI). A retrospective review of IUI pregnancies was conducted. Patients with antisperm antibodies, a low hypo-osmotic swelling (HOS) test score (< 50%), or those using donor sperm were excluded. A total of 52 couples were enrolled in the study: 34 in the normal motile density (MD) group and 18 in the low MD group. The SAB rate in the normal group was 29.4% and in the low group was 27.8%. Thus, these data fail to corroborate the conclusions reached after evaluation of IVF pregnancies that low MD is a cause of SAB. However, since there is a large difference in the number of sperm that come in contact with the oocyte following IVF versus IUI, it may be that the implantation defect is not evident until the oocyte is exposed to a certain number of abnormal sperm.

Reproductive Toxicity and Tissue Concentrations of Low Doses of 2,3,7,8-Tetrachlorodibenzo-p-Dioxin in Male Offspring Rats Exposed Throughout Pregnancy and Lactation

The effects of low doses of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on the reproductive system of male offspring rats were examined. The dams were treated subcutaneously 2 weeks prior to mating and throughout mating, pregnancy, and lactation. They received an initial loading dose of 25, 60, or 300 ng TCDD/kg body wt, followed by a weekly maintenance dose of 5, 12, or 60 ng TCCD/kg body wt (TCDD 25/5, TCDD 60/12, and TCDD 300/60). Three dams per group were killed on Gestation Day 21 and the fetuses were removed. The concentration of TCDD in the maternal liver and fat was measured. After birth, developmental landmarks in male rats were monitored. At weaning, the concentration of TCDD in the offspring liver and testis was determined. Effects on male reproduction were studied on Postnatal Days (PND) 70 and 170. At weaning, the concentration of TCDD in the offspring liver was 0.24, 0.39, and 1.78 ng/g in the TCDD 25/5, TCDD 60/12, and TCDD 300/60 groups, respectively. In the testes, the concentration of TCDD was 0.25 ng/g in the TCDD 25/5 and TCDD 60/12 groups and 0.28 ng/g in the TCDD 300/60 group. The number of sperm per cauda epididymis was reduced in TCDD groups at puberty and at adulthood. Daily sperm production was permanently decreased as was the sperm transit rate in the TCDD-exposed male rats, thus increasing the time required by the sperm to pass through the cauda epididymis. Moreover, the male rats of the TCDD groups showed an increased number of abnormal sperm when investigated at adulthood. Similarly, mounting and intromission latencies were significantly increased in the TCDD 25/5 and TCDD 300/60 groups. In the highest dose group, serum testosterone concentration was decreased at adulthood. Likewise, in this dose group permanent changes including pyknotic nuclei and the occurrence of cell debris in the lumen were revealed. The lowest adverse effect level and the no observed effect level can be estimated to be substantially lower than the estimated daily dose of the lowest dose which is 0.8 ng/kg body wt/day. Sperm parameters were more susceptible than the other end points investigated. However, the question as to whether such doses exposed throughout gestation and lactation induce subtle changes in humans remains to be determined.

Standard Methods for the Examination of Water and Waste Water. A. E. Greenberg , L. S. Clesceri , A. D. Eaton

Previous articleNext article No AccessBook ReviewsStandard Methods for the Examination of Water and Waste Water. A. E. Greenberg , L. S. Clesceri , A. D. Eaton George M. Simmons, Jr.George M. Simmons, Jr. Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by Volume 12, Number 3Sep., 1993 Article DOIhttps://doi.org/10.2307/1467470 Views: 3Total views on this site Citations: 3Citations are reported from Crossref Journal History This article was published in the Journal of the North American Benthological Society (1986-2011), which is continued by Freshwater Science (2012-present). Copyright 1993 The North American Benthological SocietyPDF download Crossref reports the following articles citing this article:M. Cobo-Golpe, V. Fernández-Fernández, T. Arias, M. Ramil, R. Cela, I. Rodríguez Comparison of UV, chlorination, UV-hydrogen peroxide and UV-chlorine processes for tramadol removal: Kinetics study and transformation products identification, Journal of Environmental Chemical Engineering 10, no.33 (Jun 2022): 107854.https://doi.org/10.1016/j.jece.2022.107854Joyce Margaret Ekopai, Nathan Lubowa Musisi, Howard Onyuth, Benigna Gabriela Namara, Celsus Sente Determination of Bacterial Quality of Water in Randomly Selected Swimming Pools in Kampala City, Uganda, New Journal of Science 2017 (Jan 2017): 1–7.https://doi.org/10.1155/2017/1652598M.F. Lasheidani, S.N. Balouchi, A. Keyvan, S. Jamili, K. Falakrou Effects of Butachlor on Density, Volume and Number of Abnormal Sperms in Caspian Kutum (Rutilus frisii kutum, Kamenskii 1901), Research Journal of Environmental Sciences 2, no.66 (Jun 2008): 474–482.https://doi.org/10.3923/rjes.2008.474.482

Ecology of Teleost Fishes. Robert J. Wootton

Previous articleNext article No AccessNew Biological BooksEcology of Teleost Fishes. Robert J. Wootton Peter B. MoylePeter B. Moyle Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The Quarterly Review of Biology Volume 66, Number 2Jun., 1991 Published in association with Stony Brook University Article DOIhttps://doi.org/10.1086/417202 Views: 1Total views on this site Citations: 1Citations are reported from Crossref Copyright 1991 The University of ChicagoPDF download Crossref reports the following articles citing this article:M.F. Lasheidani, S.N. Balouchi, A. Keyvan, S. Jamili, K. Falakrou Effects of Butachlor on Density, Volume and Number of Abnormal Sperms in Caspian Kutum (Rutilus frisii kutum, Kamenskii 1901), Research Journal of Environmental Sciences 2, no.66 (Jun 2008): 474–482.https://doi.org/10.3923/rjes.2008.474.482

Inhalation toxicity studies of cobalt sulfate in [formula omitted] rats and B6C3F1 mice

Groups of 10 F344 N rats and B6C3F1 mice of each sex were exposed to cobalt sulfate heptahydrate aerosols of 0, 0.3, 1.0, 3.0, 10, or 30 mg/m 3, 6 hr per day, 5 days per week, for 13 weeks. All rats and female mice and all but 2 10 male mice exposed at the top concentration survived to the end of the studies. Polycythemia was observed in exposed rats but not in mice. Sperm motility was decreased in mice exposed at 3 mg/m 3 (the lowest concentration evaluated) and at higher concentrations, and increased numbers of abnormal sperm and decreased testis and epididymal weights occurred in mice exposed to 30 mg/m 3. Cobalt content in the urine of rats increased with increasing atmospheric cobalt exposure. Primary histopathologic effects were limited to the respiratory tract. Lesions in rats and mice included degeneration of the olfactory epithelium, squamous metaplasia of the respiratory epithelium, and inflammation in the nose; inflammation, necrosis, squamous metaplasia, ulcers (rats), and inflammatory polyps (rats) of the larynx; metaplasia of the trachea (mice); and fibrosis, histiocytic infiltrates, bronchiolar epithelial regeneration, and epithelial hyperplasia in the alveoli of the lung. The most sensitive tissue was the larynx, with squamous metaplasia observed in rats and mice at the lowest exposure concentration of 0.3 mg/m 3. Thus, a no-observed-adverse-effect level was not reached in these studies.

An evaluation of the male reproductive toxicity of cathinone

(−)-Cathinone is the major psychoactive component of khat plant ( Catha edulis Forssk.). Khat has been shown to produce reproductive toxicity in human beings and experimental animals. However, the chemical constituents of khat leaves responsible for sexual dysfunction are not known. In the present study cathinone enantiomers have been investigated for their reproductive toxicity in rats. Cathinone produced a dose-dependent decrease in food consumption and suppressed the gain in body weight. There was a significant decrease in sperm count and motility and increase in the number of abnormal sperms in cathinone treated animals. Histopathological examination of testes revealed degeneration of interstitial tissue, cellular infiltration and atrophy of Sertoli and Leydig's cells in cathinone treated animals. Cathinone also produced a significant decrease in plasma testosterone levels of the rats. Although both enantiomers of cathinone produced deleterious effects on male reproductive system, (−)-cathinone was found to be more toxic. From this study it may be concluded that the cathinone content in khat may be partially or totally responsible for the reproductive toxicity in khat chewers.

Inhalation Toxicity Studies of Cobalt Sulfate in F344/N Rats and B6C3F1 Mice

Inhalation Toxicity Studies of Cobalt Sulfate in F344/N Rats and B6C3F1 Mice. BUCHER, J. R., ELWELL, M. R., THOMPSON, M. B., CHOU, B. J., RENNE, R., AND RAGAN, H. A. (1990). Fundam. Appl. Toxicol. 15, 357–372. Groups of 10 F344/N rats and B6C3F1 mice of each sex were exposed to cobalt sulfate heptahydrate aerosols of 0, 0.3, 1.0, 3.0, 10, or 30 mg/m3, 6 hr per day, 5 days per week, for 13 weeks. All rats and female mice and all but 2/10 male mice exposed at the top concentration survived to the end of the studies. Polycythemia was observed in exposed rats but not in mice. Sperm motility was decreased in mice exposed at 3 mg/m3 (the lowest concentration evaluated) and at higher concentrations, and increased numbers of abnormal sperm and decreased testis and epididymal weights occurred in mice exposed to 30 mg/m3. Cobalt content in the urine of rats increased with increasing atmospheric cobalt exposure. Primary histopathologic effects were limited to the respiratory tract. Lesions in rats and mice included degeneration of the olfactory epithelium, squamous metaplasia of the respiratory epithelium, and inflammation in the nose; inflammation, necrosis, squamous metaplasia, ulcers (rats), and inflammatory polyps (rats) of the larynx; metaplasia of the trachea (mice); and fibro-sis, histiocytic infiltrates, bronchiolar epithelial regeneration, and epithelial hyperplasia in the alveoli of the lung. The most sensitive tissue was the larynx, with squamous metaplasia observed in rats and mice at the lowest exposure concentration of 0.3 mg/m3. Thus, a no-observed-adverse-effect level was not reached in these studies

Germ and somatic cell abnormalities following in vivo administration of thymidine and adenine

It is known that an excess of or a depletion in bases and nucleosides produce genetic effects in vitro, and a similar effect has been found with the nucleoside thymidine in this laboratory in vivo. To confirm this effect and to see if this occurs with the base adenine, thymidine and adenine were administered to male mice by i.p. injection and the sperm examined for head-shape abnormalities 4 and 5 weeks later. Treated males also were mated to untreated females for the provision of an F 1 generation. The F 1 males were subjected to the sperm morphology assay when they reached 14 weeks of age. Amongst those F 0 males given adenine, there was a dose-related increase in the frequency of abnormal sperm and the group given thymidine also showed increases, confirming the results of previous studies in this laboratory. In the F 1 generation, the fraction of mice from treated males showing increases in numbers of abnormal sperm was greater than that of the controls. In a micronucleus test with mice treated with thymidine, mitosis was delayed and there was a marginal increase in micronuclei, suggesting that an imbalance in nucleoside pools may be responsible for chromosomal damage in somatic cells in vivo. Therefore it is considered that similar effects to those produced in vitro can be demonstrated in vivo. Furthermore, the results of the sperm morphology assay show that the damage is transmissible.

Sperm shape abnormality and urine mutagenicity in mice treated with niclosamide

Niclosamide, a widely used anthelmintic drug in underdeveloped countries, is known to be mutagenic in the Salmonella typhimurium microsomal test system. The urine obtained from mice treated with niclosamide is mutagenic in the TA98 and TA1538 strains. Its effects on mouse-sperm morphology were evaluated in CD 1 and (BALB/cJ × DBA/2J) F 1 mice after 5 daily oral niclosamide doses of either 60, 80, 100 or 120 mg/kg. A statistically significant increase in abnormal sperm morphology was detected in both CD 1 and (BALB/cJ × DBA/2J) F 1 mice. No drug-related effects on testis weight nor on sperm count were observed in either genotype. Urine samples obtained from niclosamide-treated F 1 mice were assayed with the Salmonella typhimurium strain TA1538 both in the absence and presence of β-glucuronidase. In the absence of glucuronidase, urine mutagenicity increased with increasing dose and the highest doses were toxic. In the presence of glucuronidase, urine mutagenicity and toxicity also increased. Only at the highest dose (120 mg/kg), however, was there a positive correlation between the urine mutagenic activity and an increase in the number of abnormal sperm. The results of this study suggest that the increase in abnormal sperm depends on the systemic presence of non-conjugated niclosamide metabolites.

Effect on turkey spermatozoa of a frothy fluid derived from the cloaca of a male turkey

The influence on turkey spermatozoa of a frothy fluid derived from the cloacal region of a male turkey was investigated. The frothy fluid was collected from the turkey tom during mounting, and semen for the experiment was obtained from the ductus deferens removed after necropsy. Spermatozoa diluted with frothy fluid were examined for motility, viability, and fertilizing capacity and compared with semen diluted with phosphate buffer or undiluted ductal semen. The life-span of spermatozoa suspended in frothy fluid was slightly prolonged during in vitro storage as compared with the undiluted semen or the semen diluted with phosphate buffer; however, a rapid increase of the number of deformed spermatozoa during storage was observed in the semen diluted with frothy fluid. The fertilizing ability of spermatozoa was not influenced by the dilution with frothy fluid when the diluted spermatozoa were inseminated intravaginally immediately after the dilution. On the contrary, when spermatozoa suspended in frothy fluid were preserved at 0 C for 24 h, their fertilizing capacity decreased drastically, probably due to the increased number of abnormal spermatozoa during in vitro preservation.

Scoring sperm morphology from fertile and infertile cigarette smokers using the scanning electron microscope and image analysis

Image analysis was applied to photographs of sperm samples obtained using a scanning electron microscope. This technique is too time-consuming for routine use but could, if automated, provide an objective assessment of sperm morphology. In order to test the technique, sperm samples were evaluated from four groups of men: fertile and infertile smokers and fertile and infertile nonsmokers. There was a significant increase in the numbers of abnormalities in samples from infertile men. There was no association between the numbers of abnormal sperm and cigarette smoking.

Effects of ethylene glycol monomethyl ether (EGME) on mating performance and epididymal sperm parameters in F344 rats

Previous histologic studies on the effects of EGME identified dividing spermatocytes as a primary target cell type in the testis. The following studies were undertaken to assess possible effects of EGME on late-stage and epididymal spermatids, and spermatogonia. Adult male F344 rats ( n = 20/group) of proven fertility were dosed po with 0, 50, 100, or 200 mg EGME/kg/day for 5 days. Each male was then mated with two females/week for 8 weeks. Females were sacrificed ca. 2 weeks after removal from the male, and number of live and dead fetuses, resorption sites, and corpora lutea were noted. Additional males were treated similarly, sacrificed at weekly intervals, and measures of epididymal sperm count, motility, and morphology were made. The fertility of males treated with 200 mg EGME/kg declined at Week 4, and remained low for the rest of the study. There was a modest but significant increase in the number of resorption sites at Weeks 5 and 6 in the high dose group. There was a decrease in the number of litters sired at Week 5 after dosing in the 100-mg EGME/kg group. There were time- and dose-related decreases in sperm concentration and motility, primarily in the 100- and 200-mg/kg groups, as well as concurrent elevations in the number of abnormal sperm forms in the epididymis. These studies show that EGME is a very weak inducer of dominant-lethal mutations, and produces previously undescribed effects on late-stage spermatids and spermatogonia.