For decades, studies of endocrine-disrupting chemicals (EDCs) have challenged traditional concepts in toxicology, in particular the dogma of “the dose makes the poison,” because EDCs can have effects at low doses that are not predicted by effects at higher doses. Here, we review two major concepts in EDC studies: low dose and nonmonotonicity. Low-dose effects were defined by the National Toxicology Program as those that occur in the range of human exposures or effects observed at doses below those used for traditional toxicological studies. We review the mechanistic data for low-dose effects and use a weight-of-evidence approach to analyze five examples from the EDC literature. Additionally, we explore nonmonotonic dose-response curves, defined as a nonlinear relationship between dose and effect where the slope of the curve changes sign somewhere within the range of doses examined. We provide a detailed discussion of the mechanisms responsible for generating these phenomena, plus hundreds of examples from...

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Hormones and endocrine-disrupting chemicals: Low-dose effects and nonmonotonic dose responses

The concept of "reproductive strategy" drawn from the field of behavioral ecology is applied to the study of childhood experience and interpersonal development in order to develop an evolutionary theory of socialization. The theory is presented in terms of 2 divergent development pathways considered to promote reproductive success in the contexts in which they have arisen. One is characterized, in childhood, by a stressful rearing environment and the development of insecure attachments to parents and subsequent behavior problems; in adolescence by early pubertal development and precocious sexuality; and, in adulthood, by unstable pair bonds and limited investment in child rearing, whereas the other is characterized by the opposite. The relation between this theory and prevailing theories of socialization, specifically, attachment, social-learning, and discrete-emotions theory, is considered and research consistent with our evolutionary theory is reviewed. Finally, directions for future research are discussed.

https://www.jstor.org/stable/pdfplus/1131166.pdf

Childhood Experience, Interpersonal Development, and Reproductive Strategy: An Evolutionary Theory of Socialization.

Why do some people prefer heterosexual love while others fancy the same sex? Is sexual identity biologically determined or a product of convention? In this brilliant and provocative book, the acclaimed author of Myths of Gender argues that even the most fundamental knowledge about sex is shaped by the culture in which scientific knowledge is produced.Drawing on astonishing real-life cases and a probing analysis of centuries of scientific research, Fausto-Sterling demonstrates how scientists have historically politicized the body. In lively and impassioned prose, she breaks down three key dualisms - sex/gender, nature/nurture, and real/constructed - and asserts that individuals born as mixtures of male and female exist as one of five natural human variants and, as such, should not be forced to compromise their differences to fit a flawed societal definition of normality.

Sexing the body :gender politics and the construction ofsexuality

/pdf/sexing-the-body-gender-politics-and-the-construction-of-2oorhr6twp.pdf

Sexing the Body: Gender Politics and the Construction of Sexuality

In this article, the author argues that we need to conceptualize gender as a social structure, and by doing so, we can better analyze the ways in which gender is embedded in the individual, interactional, and institutional dimensions of our society. To conceptualize gender as a structure situates gender at the same level of general social significance as the economy and the polity. The author also argues that while concern with intersectionality must continue to be paramount, different structures of inequality have different constructions and perhaps different influential causal mechanisms at any given historical moment. We need to follow a both/and strategy to understand gender structure, race structure, and other structures of inequality as they currently operate while also systematically paying attention to how these axes of domination intersect. Finally, the author suggests we pay more attention to doing research and writing theory with explicit attention to how our work can indeed help transform as w...

Gender As a Social Structure Theory Wrestling with Activism

The sexual behavior of male and female guinea pigs from mothers receiving testosterone propionate during most of pregnancy was studied after the attainment of adulthood. As a part of the investigation, the responsiveness of the females to estradiol benzoate and progesterone and to testosterone propionate was determined. The larger quantities of testosterone propionate produced hermaphrodites having external genitalia indistinguishable macroscopicalty from those of newborn males. Gonadectomized animals of this type were used for tests of their responsiveness to estradiol benzoate and progesterone and to testosterone propionate. The capacity to display lordosis following administration of estrogen and progesterone was greatly reduced. Male-like mounting behavior, on the other hand, was displayed by many of these animals even when lordosis could not be elicited. Suppression of the capacity for displaying lordosis was achieved with a quantity of androgen less than that required for masculinization of the exte...

Organizing action of prenatally administered testosterone propionate on the tissues mediating mating behavior in the female guinea pig.

An exploratory study of the effect of social isolation variables on the sexual behaviour of male guinea pigs

Several investigators have reported that interruption of the mating pattern of male rats results in fewer copulations preceding ejaculation than are usually recorded in the free-mating situation. Apparently, the first study of this effect was made by Rasm~ssen.~ Beach and his coworkers (1) have also observed the same phenomenon during experiments in the Yale laboratory. In a recent monograph (4), Larsson has described several studies in which the duration and nature of the interruptions were varied systematically and the consequent change in sexual performance of male rats was measured. Before the aforementioned studies were known to the present investigator, he noted that male guinea pig behavior was influenced markedly by interference with the mating sequence whether by E or the female guinea pig used in the test. A pilot study was initiated to determine whether these observations were reliable and potentially useful. The study, it turned out, was merely a repetition of a part of the research completed by Larsson. Although the findings were not novel, the report has value in that a different laboratory animal was used, increasing the generality of results. METHOD Szlbjects.-11 male guinea pigs from a genetically heterogeneous strain between the ages of 150-250 days were used. They were relatively tame and were accustomed to being handled by E. Ss were selected from a larger group on the basis of their possessing a high probability of ejaculation which was determined during several pre-experimental 10-min. mating tests. The males were caged in pairs and had no access to females except during the testing period.

http://prx.sagepub.com/content/4/3/215.full.pdf

Effect of Interruption of Copulation on Male Guinea Pig Sexual Behavior

Beginning at the first or second day of life, dosages of 500 µg. of testosterone propionate per 100 gm. body weight were administered daily to intact and castrated guinea pigs. There was no statistically significant evidence that the intromission and ejaculation responses developed precociously in these animals, when compared with intact guinea pigs receiving sesame oil. These results differ from those obtained with the rat in which precocious sexual development has been produced by testosterone propionate treatment. It was concluded from the accumulated evidence that the guinea pig and rat do not respond similarly to testosterone propionate during post-natal development and maturity.

Arnold A. Gerall

Papers

Organizing action of prenatally administered testosterone propionate on the tissues mediating mating behavior in the female guinea pig.

An exploratory study of the effect of social isolation variables on the sexual behaviour of male guinea pigs

Effect of Interruption of Copulation on Male Guinea Pig Sexual Behavior

An attempt to induce precocious sexual behavior in male guinea pigs by injections of testosterone propionate.