Acute toxicity of sodium arsenite in a complex food matrix.

Acute toxicity of a single oral dose of sodium arsenite (As), administered in half and half cream (HH), was assessed in male and non-pregnant female rats (0.41, 4.1, 41.0 and 410.0mg/kg body weight) and pregnant rats (0.41, 4.1 and 41.0mg/kg body weight). Control rats received deionized water alone, HH alone or 41.0mg/kg As in deionized water (41 mg/kg As-water). Male and non-pregnant rats were monitored for 14 consecutive days post-dosing. Pregnant rats, dosed on gestation day 10 (GD-10), were monitored until fetuses were collected on GD 20. High mortality (100%) was observed in male and non-pregnant female rats exposed to 410.0mg/kg As-HH. Low mortality (25%) was observed in non-pregnant female rats exposed to 41 mg/kg As-water. No mortality was observed in other control or treated groups. Reduced female fetal numbers were observed in the 41 mg/kg As-water group but not in the other control groups. Developmental effects were not observed in the controls or the As-HH treatment groups. In conclusion, As toxicity was not reduced when a high dose (410 mg/kg) was administered in HH however, at lower doses (41 mg/kg), HH reduced acute As oral toxicity in the female and developing fetus.

Effects of oral androstenedione on phospholipid fatty acids, ATP, caspase-3, prostaglandin E(2) and C-reactive protein in serum and livers of pregnant and non-pregnant female rats.

Androstenedione, a steroidal dietary supplement taken to enhance athletic performance, could affect serum and liver lipid metabolism, induce liver toxicity or alter inflammatory response depending on dose and duration of exposure. Pregnancy could further exaggerate these effects. To examine this, mature female rats were gavaged with 0, 5, 30 or 60 mg/kg/day androstenedione beginning two weeks prior to mating and continuing through gestation day 19. Non-pregnant female rats were gavaged over the same time frame with 0 or 60 mg/kg/day androstenedione. Serum was collected and livers were removed from dams on gestation day 20 and from non-pregnant rats after 5 weeks of treatment. Androstenedione had no effect on serum total cholesterol, triglycerides or HDL-cholesterol, but significantly decreased C-reactive protein in pregnant rats and prostaglandin E(2) in serum of both pregnant and non-pregnant rats. There were treatment related decreases in liver ATP and, to a lesser degree, caspase-3 and no change in alkaline phosphatase of pregnant female rats. Androstenedione decreased docosahexaenoic acid in both serum and liver phospholipids of pregnant female rats. In conclusion, oral androstenedione did not result in overt hepatotoxicity in pregnant female rats, but produced modest changes in lipid metabolism and may impair regeneration of injured hepatic cells or tissue.

Effects of oral androstenedione on steroid metabolism in liver of pregnant and non-pregnant female rats.

It is unknown whether androstenedione, a steroidal dietary supplement taken to enhance athletic performance, can affect physiological hormone levels by altering liver enzyme activities that metabolize steroid hormones. Altered hormone levels could be especially devastating during pregnancy. Mature female rats were gavaged with 0, 5, 30 or 60 mg/kg/day androstenedione beginning two weeks prior to mating and continuing through gestation day 19. Non-pregnant female rats were gavaged over the same time frame with 0 or 60 mg/kg/day androstenedione. Livers were removed from dams on gestation day 20 and from non-pregnant rats after five weeks' treatment. Liver microsomes were incubated with 200 microM testosterone, and the reaction products were isolated and analyzed by HPLC. In pregnant rats, formation of 6alpha-, 15beta-, 7alpha-, 16beta-, and 2beta-hydroxytestosterone was increased significantly vs. control at the highest dose level only. Formation of 6beta-hydroxytestosterone increased significantly at both the 30 and 60 mg/kg/day dose levels. In non-pregnant rats, 60 mg/kg/day androstenedione significantly increased formation of 15beta-, 6beta-, 16beta-, and 2beta-hydroxytestosterone. The data suggest that high oral doses of androstenedione can induce some female rat liver cytochromes P450 that metabolize steroid hormones and that the response to androstenedione does not differ between pregnant and non-pregnant female rats.

Restoration of spermatogenesis by exogenously administered testosterone in rats made azoospermic by hypophysectomy or withdrawal of luteinizing hormone alone.

The major objective of the studies presented herein was to compare the extent to which exogenously administered testosterone is able to restore spermatogenesis in adult rats made azoospermic by withdrawal of all pituitary hormones (hypophysectomy for 4 weeks) vs. withdrawal of LH alone [testosterone- and estradiol-filled (TE) polydimethylsiloxane implants of 2.5 and 0.1 cm, respectively, for 8 weeks]. In hypophysectornized (Hypox) rats, serum LH and FSH were both undetectable; in the rats that received TE implants, serum LH was undetectable, but FSH was unaffected compared to control values. Seminiferous tubule fluid testosterone concentrations were reduced significantly from their control values of 60-65 to 1.4-1.7 ng/ml in the azoospermic Hypox and TE rats. These rats then received testosterone-filled implants of 4, 12, 18, or 24 cm and were killed 2 months later. In both the Hypox and TE rats, seminiferous tubule fluid testosterone concentrations rose linearly with increasing capsule sizes, and with each of the implant sizes, these concentrations did not differ significantly between the Hypox and TE rats. This made it possible for the first time to examine the effects of comparable intratesticular testosterone concentrations on the numbers of advanced spermatids per testis that could be restored in the azoospermic testes of rats lacking all pituitary factors vs. those lacking only LH. The results that we present demonstrate that the numbers of restored advanced spermatids were consistently and significantly lower in Hypox than in TE rats despite equivalent seminiferous tubule fluid testosterone concentrations. These results provide quantitative conclusive evidence to support the contention that pituitary factors in addition to LH are required for the quantitative restoration of spermatogenesis in the adult rat testis.

To what extent can spermatogenesis be maintained in the hypophysectomized adult rat testis with exogenously administered testosterone?

In a previous study it was demonstrated that spermatogenesis can be maintained quantitatively with exogenously administered testosterone in adult intact rats that lack LH. The studies described herein were designed to examine the extent to which spermatogenesis can be maintained quantitatively with exogenously administered testosterone in adult rats that lack all pituitary hormones. Adult male rats were hypophysectomized and testosterone was administered at the time of hypophysectomy via sustained release polydimethylsiloxane (PDS) capsules of increasing lengths. We used the PDS capsules to clamp testosterone at defined concentrations within the seminiferous tubule fluid over a 2- to 3-month treatment period. Mean testis weights and advanced spermatid numbers per testis stabilized by 8 weeks of testosterone treatment regardless of testosterone dose. Both testis weight and advanced spermatid number responded to testosterone dose, reaching plateaus of 1.2 g and 170 x 10(6) per testis, respectively. These values were 60% of, and significantly less than, the respective control values. This result was in striking contrast to the results of our previous study of LH-suppressed intact rats, in which exogenously administered testosterone resulted in testis weights and advanced spermatid numbers that plateaued at values not significantly different from those in controls. These different effects of testosterone in intact and hypophysectomized rats occurred despite the fact that the seminiferous tubule fluid testosterone concentrations achieved in the hypophysectomized rats (up to 25 ng/ml) were greater than the minimal testosterone concentration found previously to be required to maintain spermatogenesis quantitatively in LH-suppressed intact rats (13 ng/ml). Taken together, these results demonstrate clearly that intratesticular testosterone doses that are as high as or higher than those that maintain spermatogenesis quantitatively in intact rats lacking LH fail to maintain spermatogenesis quantitatively in rats lacking all pituitary hormones.

Restoration of advanced spermatogenic cells in the experimentally regressed rat testis: quantitative relationship to testosterone concentration within the testis.

We examined the effect of exogenously administered testosterone (T) on the quantitative restoration of advanced spermatogenic cells in adult rat testes rendered azoospermic by treating rats with polydimethylsiloxane (PDS) implants of T and estradiol (E). Experimental rats received PDS-TE implants for an initial 8-week period; control rats received empty implants. By 8 weeks of PDS-TE treatment, rats became severely oligospermic, and the T concentration within the seminiferous tubule fluid (STF) was reduced approximately 80% (from 57.8 ng/ml in controls to 9.6 ng/ml). After the initial 8-week PDS-TE treatment, PDS-TE implants were removed from one group of rats; a second group of PDS-TE-implanted rats received an additional PDS-T implant of 24 cm. Eight weeks after the removal of PDS-TE implants or the implantation of additional T, testis weight and numbers of advanced spermatogenic cells were restored to those of control rats. The STF T concentration 8 weeks after the removal of PDS-TE implants also was restored to that in control rats. In contrast, the STF T concentration increased to only 40% of control values in the rats that received an additional T implant. Despite this 60% reduction in T concentration compared to the control value, advanced spermatogenic cell number was restored to a value indistinguishable from that of intact controls. These observations indicate that spermatogenesis can be quantitatively restored in PDS-TE-implanted rats with exogenously administered T, and moreover, that this restoration does not require the high T concentration found in the STF of intact control rats.

Reversal of long-term LH deprivation on testosterone secretion and Leydig cell volume, number and proliferation in adult rats.

The purpose of this study was to determine whether Leydig cell volume and function could recover fully from long-term LH deprivation upon restoration of endogenous LH secretion, and whether the restoration of LH would elicit a mitogenic response, i.e. stimulate Leydig cell proliferation or affect Leydig cell number per testis. LH secretion was inhibited by treating adult rats with testosterone and oestradiol-filled (TO) silicone elastomer implants (16 weeks), and was restored by removing the implants. Changes in serum concentrations of LH and FSH, LH-stimulated testosterone secretion by testes perfused in vitro, Leydig cell volume and number per testis, average Leydig cell volume and Leydig cell [3H]thymidine incorporation were measured at weekly intervals following implant removal. The TO implants inhibited (P less than 0.01) LH secretion, but serum concentrations of FSH were not significantly different (P greater than 0.10) from control values. After implant removal, serum LH returned to control values within 1 week, whereas serum FSH increased twofold (P less than 0.01) and returned to control values at 4 weeks. LH-stimulated in-vitro testosterone secretion was inhibited by more than 99% in TO-implanted rats, but increased (P less than 0.01) to 80% of control values by 8 weeks after implant removal. The total volume of Leydig cells per testis and the volume of an average Leydig cell were 14 and 19% of control values respectively, after 16 weeks of TO implantation (P less than 0.01), but returned to 83 and 86% of controls (P greater than 0.10) respectively, by 6 weeks after implant removal. Leydig cell proliferation ([3H]thymidine labelling index) was low (less than 0.1%) in both control and TO-implanted rats, increased (P less than 0.01) fivefold from 1 to 4 weeks after implant removal and then declined to control values at 6 weeks. The increase in Leydig cell [3H]thymidine incorporation was mimicked by treating TO-implanted rats with exogenous LH, but not FSH. Leydig cells were identified in both the interstitium and the lamina propria of the seminiferous epithelium. The proportion of Leydig cell nuclei in the lamina propria was 30-fold greater (P less than 0.01) at 1 and 3 weeks after implant removal (3%) compared with that for control and TO-implanted rats (0.1%). Total Leydig cell number per testis was marginally but not significantly (P = 0.06) decreased in rats treated with TO implants for 16 weeks when compared with controls (18.4 +/- 2.2 vs 25.4 +/- 1.2 x 10(6)).(ABSTRACT TRUNCATED AT 400 WORDS)

Is Leydig cell steroidogenic function affected by the germ cell content of the seminiferous tubules?

The effect of testicular germ cell content on Leydig cell steroidogenic function in vivo in adult rats was examined. Three experimental paradigms were used to effect germ cell changes. First, a vitamin A-depletion/repletion regimen was used to achieve synchrony at different stages of the cycle of the seminiferous epithelium and thus produce testes with widely differing germ cell contents. Second, long term vitamin A depletion was used to effect germ cell, but not Leydig cell, loss. Third, Leydig cells and germ cells first were eliminated from the testes of adult rats by the administration of ethane 1,2-dimethane sulfonate (EDS) along with testosterone- and estradiol-filled Silastic capsules; Leydig cells were then restored to the germ cell-depleted testes by removal of the luteiniging hormone (LH)-suppressing capsules. Serum, interstitial fluid, and seminiferous tubule fluid testosterone concentrations did not differ between rats in which at least 70% of the seminiferous tubules contained germ cells at stages VII-VIII or at stages XII-III of the cycle. The capacity of the testes of these rats to produce testosterone, assessed by their in vitro perfusion with maximally stimulating LH, also showed no differences despite the differences in germ cell content. Elimination of germ cells throughout the testes by long term vitamin A depletion also did not affect the steroidogenic function of the testes. Finally, the steroidogenic function of Leydig cells restored to germ cell-depleted testes was indistinguishable from that of germ cell-containing controls. These results, taken together, provide evidence supporting the contention that the germ cell content of the testis has little or no effect on testicular steroidogenic function.

Does ethane 1,2-dimethanesulphonate (EDS) have a direct cytotoxic effect on the seminiferous epithelium of the rat testis?

The authors examined the possibility that ethane 1,2-dimethanesulphonate (EDS) has a cytotoxic effect on spermatogenesis that is not secondary to androgen withdrawal resulting from the well known cytotoxic effect of EDS on Leydig cells. Adult male rats were implanted with polydimethylsiloxane (PDS) capsules containing testosterone (T) and estradiol (E), and were simultaneously injected with EDS. The PDS-TE implants, by inhibiting luteinizing hormone (LH) production, prevented Leydig cells from repopulating the testis and clamped testosterone within the seminiferous tubules at increasing concentrations relative to implant size. In rats that received EDS alone, the number of advanced spermatids per testis was significantly reduced by 2 weeks, but within 8 weeks returned to the numbers maintained in vehicle-injected control rats or in vehicle-injected rats that received testosterone- and estradiol-filled capsules of 24 cm and 0.1 cm, respectively (PDS-24TE). Surprisingly, in rats that received an EDS injection plus PDS-24TE implants, the number of advanced spermatids per testis was significantly reduced at 8 weeks and severe seminiferous tubule atrophy occurred despite the fact that the testosterone concentration was sufficient to quantitatively maintain spermatogenesis in vehicle-injected rats. In rats injected with EDS and implanted with 24 cm testosterone but not estradiol-filled capsules (PDS-24T), the advanced spermatid number per testis was significantly higher than that in the EDS plus PDS-24TE rats, but significantly lower than that in control rats. These results suggest that EDS may have a cytotoxic effect on the seminiferous epithelium that is independent of the elimination of Leydig cells, and the EDS and estradiol act synergistically to exert a profound toxic effect on spermatogenesis.

Spermiogenesis in the bullfrog (Rana catesbeiana): a study of cytoplasmic events including cell volume changes and cytoplasmic elimination.

The process by which spermatid cytoplasmic volume is reduced and cytoplasm eliminated during spermiogenesis was investigated in the bullfrog Rana catesbeiana. At early phases of spermiogenesis, newly formed, rounded spermatids were found within spermatocysts. As acrosomal development, nuclear elongation, and chromatin condensation occurred, spermatid nuclei became eccentric within the cell. A cytoplasmic lobe formed from the caudal spermatid head and flagellum and extended toward the seminiferous tubule lumen. The cytoplasmic lobe underwent progressive condensation whereby most of its cytoplasm became extremely electron dense and contrasted sharply with numerous electron-translucent vesicles contained therein. At the completion of spermiogenesis, many spermatids with their highly condensed cytoplasm still attached were released from their Sertoli cell into the lumen of the seminiferous tubule. There was no evidence of the phagocytosis of residual bodies by Sertoli cells. Because spermatozoa are normally retained in the testis in winter and are not released until the following breeding season, sperm were induced to traverse the duct system with a single injection of hCG. Some spermatids remained attached to their cytoplasm during the sojourn through the testicular and kidney ducts; however, by the time the sperm reached the Wolffian duct, separation had occurred. The discarded cytoplasmic lobe (residual body) appeared to be degraded with the epithelium of the Wolffian duct. It was determined that the volume of the spermatid was reduced by 87% during spermiogenesis through a nuclear volume decrease of 76% and cytoplasmic volume decrease of 95.3%.

Spermiogenesis in the red-ear turtle (Pseudemys scripta) and the domestic fowl (Gallus domesticus): a study of cytoplasmic events including cell volume changes and cytoplasmic elimination.

Nuclear and cytoplasmic volume changes as well as the elimination of residual spermatid cytoplasm were investigated in the red-ear turtle (Pseudemys scripta) and the rooster (Gallus domesticus). Nuclei of newly formed spermatids which were originally centrally located became eccentrically located within the cell in both species. Shortly thereafter the nuclear pole of the spermatid was found situated within deep crypts of a Sertoli cell. The cytoplasm of elongating spermatids was displaced along the nonacrosomal region of the nucleus and the proximal flagellum. In both species sheetlike Sertoli cell processes indented spermatid cytoplasm adjacent to the nucleus and appeared to segregate small packets of the cytoplasm. In the turtle, these packets of cytoplasm were separated from the spermatid. In both the turtle and rooster, a portion of the spermatid cytoplasm was displaced forward over the acrosomal region of the spermatid to resemble a hood. As spermatids were transported to the seminiferous tubular lumen, cytoplasmic lobes which projected forward of the spermatid head were formed by preferential flow of cytoplasm into one aspect of the cytoplasmic hood. In both species, at sperm release the cytoplasmic lobe was disengaged from the spermatid head to form a large residual body that was internalized and degraded within the Sertoli cell. Medium-sized cytoplasmic lobes were pinched from the head and neck region of the turtle and rooster spermatids, respectively. In the turtle, small-sized mitochondrial-rich cytoplasmic fragments budded from the caudal head and midpiece of the spermatids and were phagocytosed by the Sertoli cell. Thus, cytoplasmic elimination occurred through 1) segregation of cytoplasmic packets by Sertoli penetrating processes (turtle), 2) elimination of large and medium-sized residual bodies from the head (turtle and bird), and 3) budding of small mitochondrial-rich cytoplasmic fragments from the region of the midpiece (turtle). In the turtle a 79% reduction in total cell volume occurred during spermiogenesis which was the result of an 84% cytoplasmic reduction and a 78% nuclear reduction. During spermiogenesis, the rooster lost 97% of its total cell volume due to a 97% cytoplasmic volume change and a 96% nuclear volume change.

Spermiogenesis in the bluegill (Lepomis macrochirus): a study of cytoplasmic events including cell volume changes and cytoplasmic elimination.

The process involved in the reduction of both nuclear and cytoplasmic volume was investigated in the bluegill (Lepomis macrochirus), a teleost fish. Young spermatids contained centrally positioned nuclei which, with time, moved toward the cell surface to become eccentrically positioned. Chromatin condensation was initiated from a region near the implantation fossa, whereas at the opposite pole of the nucleus an area sparse in heterochromatin (clear area) was noted. The nuclear membrane lying adjacent to the clear area dissolved and subsequently reformed, yielding a nucleus with a reduced volume. During this process, packets of cytoplasm surrounded by a double membrane were formed along the future midpiece. The packets of cytoplasm migrated toward the cell surface, protruded from the surface, and were extruded into the spermatocyst lumen. These structures, termed residual bodies, were subsequently endocytosed, accumulated into large phagocytic vacuoles, and eventually degraded by the nearby Sertoli cell. When the spermatocyst ruptured, spermatozoa containing sparse cytoplasm were released into the excurrent duct system. During spermiogenesis, both the nuclear and cytoplasmic volumes decreased substantially (80%, 92% respectively) leading to an overall 87% reduction in total cell volume.

Effect of intratesticular injection of sodium fluoride on spermatogenesis.

The potential of sodium fluoride to affect spermatogenesis in the rat was assessed by intratesticular injection. Experimental rats' left testis was injected with sodium fluoride (50, 175 and 250 ppm) in vehicle (0.9% physiological saline); control testes were injected with vehicle. The right testis served as a non-injected control. Testicular tissues collected 'at' and 'distal to' the injection site and from the non-injected control testes were evaluated microscopically 24 hr and 1, 2 and 3 wk post-injection. Testicular tissues obtained at and distal to the injection site in all fluoride-injected groups resembled tissues collected from corresponding areas in the controls. Seminiferous tubule damage observed in both the vehicle-injected control testes and the fluoride-injected testes but not in the non-injected testes was attributed to injection trauma. Polymorphonuclear leucocyte infiltration was observed 24 hr post injection only at the injection site in the vehicle- and fluoride-injected groups. Leydig cells were unaffected. Leucocyte infiltration with seminiferous tubule damage was not considered to be a fluoride treatment-related effect because it was observed in both vehicle- and fluoride-injected testes. The results demonstrate that the rat is not adversely affected by direct exposure to fluoride at levels 200 times greater than those under normal conditions.

Testing the potential of sodium fluoride to affect spermatogenesis: a morphometric study.

This study provides quantitative information on the effect of sodium fluoride (NaF) on the testes of F1 generation male rats exposed in utero and during lactation to NaF at one of four concentrations (25, 100, 175, 250 ppm). At weaning, the F1 generation males were exposed to NaF in their drinking water for 14 weeks, after which time testicular tissues were perfusion-fixed with glutaraldehyde and observed after being embedded in plastic. The seminiferous tubules comprised 89%, 87%, 88%, 88% and 88% of the total testis volume while the interstitial space occupied 9.3%, 11.2%, 10.2%, 9.8% and 9.9% of the total testis volume for the 0, 25, 100, 175 and 250 ppm NaF treatment groups, respectively. Statistically significant differences between control and NaF-treated rats were not observed with respect to absolute volume of the seminiferous tubules, interstitial space, Leydig cells, blood vessels boundary layer, lymphatic space, macrophages, tubular lumen or absolute tubular length and absolute tubular surface area, mean Sertoli cell nucleoli number per tubular cross-section, mean seminiferous tubule diameter and the mean height of the seminiferous epithelium. A statistically significant decrease in the absolute volume and volume percent of the lymphatic endothelium was observed in the 175 and 250 ppm NaF-treated groups and in the testicular capsule in the 100 ppm NaF-treated groups. The significance of this finding is unknown at the present time. Overall, the quantitative information obtained suggests that exposure to NaF at the doses used in the present study does not adversely affect testis structure or spermatogenesis in the rat.

Testing the potential of flaxseed to affect spermatogenesis: morphometry.

Quantitative information was collected on male reproductive effects of maternal and postnatal dietary exposure to flaxseed (20 or 40%), flaxmeal (13 or 26%) or standard NIH AIN-93 feed (0% flaxseed control). Measurements were made on the testes of F1 generation males rats (1) whose mothers were exposed to the diets designated above, and (2) who, after weaning, were placed on the same diet as their mothers for an additional 70 days. The seminiferous tubules comprised 86%, 84%, 84%, 84% and 85% of the total testis volume while the interstitial space comprised 12%, 14%, 14%, 14%, 13% of the total testis volume for the 0% flaxseed/flaxmeal, 20% flaxseed, 13% flaxmeal, 40% flaxseed and 26% flaxmeal groups, respectively. Statistically significant decreases in the absolute volume of the seminiferous tubules were observed in the 20% and 40% flaxseed-treated groups when these groups were compared to controls. Borderline statistically significant differences were also observed when Sertoli cell nucleolar number per tubular cross-section were compared in the 13% flaxmeal and 20% flaxseed treatment groups. These effects were not considered biologically significant because other parameters of male reproductive function appeared normal. Overall, the quantitative information obtained suggests that exposure to flaxseed/flaxmeal at the doses used in the present study does not adversely affect testis structure or spermatogenesis in the rat.

Testing the potential of sodium fluoride to affect spermatogenesis in the rat.

The potential of sodium fluoride (NaF) to affect spermatogenesis and endocrine function was assessed in P and F1 generation male rats. Male and female experimental rats received sodium fluoride in their drinking water at one of four concentrations (25, 100, 175, 250 ppm). P generation male and female rats were exposed to sodium fluoride in their drinking water for 10 wk and then males were mated to females within the same treatment groups. Reproductive tissues were collected from P generation male rats after approximately 14 wk of treatment. Pregnant females (P) were exposed to sodium fluoride via their drinking water through gestation and lactation. F1 generation weanling male rats remained within the same treatment groups as their parents. F1 generation male rats were exposed to sodium fluoride in their drinking water for 14 wk, at which time reproductive tissues were collected. Dose-related effects were not observed within the P and F1 treatment groups in testis weights, prostate/seminal vesicle weights, non-reproductive organ weights, testicular spermatid counts, sperm production per gram of testis per day, sperm production per gram of testis, LH, FSH or serum testosterone concentrations. Histological changes were not observed in testicular tissues from either the P or F1 generation. We conclude that prolonged exposure to sodium fluoride in drinking water at the doses administered in this study does not adversely affect spermatogenesis or endocrine function in the P and F1 generation male rats.

The effect of maternal exposure to flaxseed on spermatogenesis in F(1) generation rats.

Pregnant Sprague-Dawley rats were exposed to a flaxseed (20 or 40%), flaxmeal (13 or 26%) or standard NIH AIN-93 (0% flaxseed control) diet throughout gestation and until their offspring were weaned. After weaning, F(1) generation males were placed in the same diet treatment groups as their mothers for 70 days. Statistically significant differences were not observed between either low-dose or high-dose flaxseed and flaxmeal-treated animals and the 0% flaxseed control animals for testis weights, homogenization resistant spermatid counts, daily sperm production rates, epididymal weights, seminal vesicle weights, seminiferous tubule fluid testosterone concentrations and the percentage of sperm abnormalities. The following statistically significant differences were observed when treated groups and the 0% flaxseed control groups were compared: (1) increases in serum LH in the 20% and 40% flaxseed treatment groups and in serum LH and testosterone in the 26% flaxmeal treatment group; (2) increases in the cauda epididymal weight from the 20% and 40% flaxseed groups; (3) increases in cauda epididymal sperm numbers/g epididymis from the 20% and 40% flaxseed and the 13% and 26% flaxmeal treatment groups; (4) a decrease in prostatic weight from the 20% flaxseed and 13% and 26% flaxmeal treatment groups. Prostate weight in the 40% flaxseed treatment group was lower but not statistically significantly different than the 0% flaxseed control group. Histological effects on spermatogenesis were not observed in either the control group, flaxmeal or the flaxseed treated groups.

Developmental toxicity of sodium fluoride measured during multiple generations.

Sodium fluoride (NaF) has been used to fluoridate drinking water in the United States since the mid 1940s. Because of the lack of reliable studies on the multigeneration effects of the compound, NaF (0, 25, 100, 175 or 250 ppm in drinking water) was given to rats continuously during three generations. Parental (F0) generation rats were treated for 10 weeks and mated within groups. At gestation day 20, caesarean sections were performed and eight F0 females per group and their litters (F1) were observed for implant status, fetal weight and length, sex and morphological development. The remaining F0 females (29-32 per group) were allowed to litter. F1 offspring (36 of each sex per group) were mated within groups, and caesarean sections were performed at gestation day 20. The F1 females and their litters (F2) were observed for implant status, fetal weight and length, sex and morphological development. In addition, F2 fetuses were evaluated for internal (soft-tissue) and skeletal development. Decreased fluid consumption for F0 and F1 dams at 175 and 250 ppm was attributed to decreased palatability of the solution. No dose-related effects in feed consumption or mean body weight gain were observed in either F0 or F1 females. Numbers of corpora lutea, implants, viable fetuses and fetal morphological development were similar in all groups. No dose-related anomalies in internal organs were observed in F2 fetuses. Ossification of the hyoid bone of F2 fetuses was significantly decreased at 250 ppm. Because of the decreased ossification of the hyoid bone, 250 ppm is considered the effect level.

Developmental effects of serum from flaxseed-fed rats on cultured rat embryos.

Gestation day 9.5 rat embryos were cultured for 45 h in serum obtained from pregnant rats that had been fed throughout gestation with either a control diet (based on the AIN-93 formulation), a diet supplemented with flaxseed (20% or 40%, w/w), or a diet supplemented with de-fatted flaxseed ("flaxseed meal", 13 or 26%, w/w). The embryos were fixed in neutral formalin at the end of culture. Overall growth and development was assessed, and the presence of abnormalities was noted. A significant inhibition of growth (as determined by crown-rump length) relative to control was observed in embryos cultured in serum from rats fed the 20% flaxseed diet. The incidence of spontaneous heart inversions was increased significantly in the embryos cultured in serum from the 20% flaxseed and 26% flaxseed meal fed rats. The incidence of flexion defects was increased significantly in embryos cultured in serum from 20% flaxseed-fed rats. The lack of an apparent dose response in any of the statistically significant effects suggests that the observed anomalies were chance occurrences unrelated to the treatment group from which serum was obtained. It is therefore concluded that diets high in flaxseed or flaxseed meal do not result in serum factors that are directly embryotoxic to organogenesis-staged rat embryos. This finding is consistent with the findings of a parallel in vivo rat teratology study where no significant embryotoxicity attributable to flaxseed exposure was observed.

The effect of vomitoxin (Deoxnivalenol) on testicular morphology, testicular spermatid counts and epididymal sperm counts in IL-6KO [B6129-IL6 [TmlKopf] (IL-6 gene deficient)] and WT [B6129F2 (wild type to B6129-IL6 with an intact IL-6 gene)] mice.

The potential of vomitoxin (VT) to affect testicular morphology and testicular and epididymal sperm counts was assessed in three strains of mice: IL-6KO [B6129-IL6 (tmlKopf) (IL-6 gene deficient)], WT [B6129F2 (wild type to B6129-IL6 with an intact IL-6 gene)] and B6C3F1 mice in a 90-day feeding study. The treated mice received VT at a concentration of 10 ppm in their diet. The body weight of VT-treated animals was significantly reduced compared with control animals. Slight changes, not statistically significant, were observed in relative testis weight and testicular spermatid counts. Histological changes were not apparent in the testes of VT-treated animals. The diameter of the seminiferous tubules, the height of the seminiferous epithelium and the number of Sertoli cell nucleoli per cross-sectioned seminiferous tubule in the VT-treated groups were not significantly different from their respective untreated controls. The IL-6KO and B6C3F1 VT-treated mice had significantly reduced cauda epididymal weights compared with their respective controls. These changes were not attributed to decreased sperm counts and this finding suggests that VT may exert an adverse affect on the epididymis.