Developmental effects of the uterine environment: dependence on fetal sex in rats

Ward, William F.; Karp, C. H.; Aceto, H.

doi:10.1530/jrf.0.0500269

Cited by 44 publications

(7 citation statements)

References 10 publications

(25 reference statements)

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“…The partial pressure of oxygen em ployed in this work exceeded standard human therapeutic levels (except for decompression sickness) [2], but even at these high oxygen dosages, only fetal and placental weights were affected. As expected, fetal weight was in fluenced by sex, while the placental weight was not [31,32], Fetal abnormalities and vari ations were within the range of reported nor mal prevalence among albino rats which is between 0.4 and 0.8% [33].…”

Section: Discussionsupporting

confidence: 73%

Effects of Hyperbaric Oxygen on Rat Embryos

Sapunar¹,

Saraga-Babić²,

Peruzović

et al. 1993

Neonatology

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The aim of the study was to investigate the toxic effects of hyperbaric oxygen (HBO) on rat embryos. Two groups of Fischer pregnant rats were exposed to oxygen at pressures of 324 and 426 kPa for 90 min per day for 5 consecutive days (8–12 days of gestation). The third group was exposed to normobaric oxygen for 12 h on the eighth day of gestation. Two control groups were used; the first was comprised of intact and the second of sham-treated animals. The HBO treatment did not significantly affect maternal weight gain or reduce litter size, nor did it induce any embryonic abnormalities. However, the fetal body weight was reduced and the placental weight increased in the groups exposed to HBO at pressures of 324 and 426 kPa. When female fetuses which had been exposed to oxygen at 324 or 426 kPa were compared to the intact control group, a reduction in wet weights of 9.2 (p < 0.05) and 12.1 % (p < 0.01), respectively, was noted. Male fetuses exposed to oxygen at 324 and 426 kPa displayed a reduced body weight of 11.7 (p < 0.01) and 16.6% (p < 0.01), respectively. Placental weight was increased by 18.9 (p < 0.01) and 23.6% (p < 0.01) in the groups exposed to oxygen at 324 and 426 kPa, respectively. These data suggest that HBO, either at 324 or 426 kPa, is not potent at inducing malformations and that the largest embryotoxic effects are upon fetal body weight and placental weight. However, the histological examination of placentas revealed alterations in labyrinthine blood vessels and a statistically significant thickening of the placental barrier. In conclusion, this study suggests that transient interference with normal placentation is probably sufficient to cause permanent maldevelopment of the placenta and embryo.

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Section: Discussionsupporting

confidence: 73%

Effects of Hyperbaric Oxygen on Rat Embryos

Sapunar¹,

Saraga-Babić²,

Peruzović

et al. 1993

Neonatology

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“…Among rats, the body weight of male fetuses is inversely related to the number of fetuses (and thus the number of males and the severity of the maternal attack?) in the ipsilateral uterine horn, but the body weight of females is not affected by the number of other fetuses present (Ward, Karp & Aceto 1977). However, animal data do not always parallel human sex ratios.…”

Section: Sex Ratios In Human Morbidity and Mortality It Is Not Alwaysmentioning

confidence: 93%

An immunoreactive theory of selective male affliction

1985

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Males are selectively afflicted with the neurodevelopmental and psychiatric disorders of childhood, a broad and virtually ubiquitous phenomenon that has not received proper attention in the biological study of sex differences. The previous literature has alluded to psychosocial differences, genetic factors and elements pertaining to male “complexity” and relative immaturity, but these are not deemed an adequate explanation for selective male affliction. The structure of sex differences in neurodevelopmental disorders is hypothesized to contain these elements: (1) Males are more frequently afflicted, females more severely; (2) disorders arising in females are largely mediated by the genotype; in males, by a genotype by environment interaction; (3) complications of pregnancy and delivery occur more frequently with male births; such complications are decisive and influence subsequent development. We hypothesize that there is something about the male fetus that evokes an inhospitable uterine environment. This “evocative principle” is hypothesized to relate to the relative antigenicity of the male fetus, which may induce a state of maternal immunoreactivity, leading either directly or indirectly to fetal damage. The immunoreactive theory (IMRT) thus constructed is borrowed from studies of sex ratios and is the only explanation consistent with negative parity effects in the occurrence of pregnancy complications and certain neurodevelopmental disorders. Although the theory is necessarily speculative, it is heuristic and hypotheses derived from it are proposed; some are confirmed in the existing literature and by the authors' research.

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“…This finding has since been replicated in mice (vom Saal & Bronson, 1978). But, in both males and females, no differences in body weight based on prior intrauterine position have been found either at birth or in adulthood (F. S. vom Saal, unpublished; Ward, Karp & Aceto, 1977;vom Saal & Bronson, 1978). In addition, Clemens, Gladue & Coniglio (1978) working with rats, and vom Saal (1978) working with mice found that administration of an anti-androgen to pregnant females during the last third of pregnancy eliminated differences in anogenital distance between females based on their proximity to male fetuses.…”

Section: Introductionmentioning

confidence: 88%

Variation in phenotype due to random intrauterine positioning of male and female fetuses in rodents

Saal¹

1981

Reproduction

180

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Rodents are polytocous mammals, and male and female fetuses can develop in utero contiguous to fetuses of the same or opposite sex. This paper describes experiments demonstrating that random intrauterine positioning of male and female fetuses results in within-sex variation in phenotype in mice and rats. This phenomenon provides a clear example of the degree to which the intrauterine environment can bias development in terms of effects on morphology, physiology and behaviour. I propose that individual differences in reproductively-related characteristics based on prior intrauterine position may play a role both in the regulation of population size in rodents and in the reproductive success of individuals as changes in population size occur.

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Developmental effects of the uterine environment: dependence on fetal sex in rats

Cited by 44 publications

References 10 publications

Effects of Hyperbaric Oxygen on Rat Embryos

Effects of Hyperbaric Oxygen on Rat Embryos

An immunoreactive theory of selective male affliction

Variation in phenotype due to random intrauterine positioning of male and female fetuses in rodents

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