Hormonal determinants in the development of masculine and feminine behavior in the female hamster

A time-resolved fluorescence immunoassay for the ultrasensitive determination of diethylstilbestrol based on the double-codified gold nanoparticles

An ultrasensitive and selective method is presented for the determination of diethylstilbestrol (DES) using time-resolved fluorescence immunoassay (TRFIA) based on double-codified gold nanoparticles (DC-AuNPs). In this system, the DC-AuNPs, that are gold nanoparticles (AuNPs) modified with anti-DES antibody and SH-dsDNA-biotin, was regarded as signal amplifier. A competitive immunoreaction was performed on polystyrene microtitration plates, where the DES compete with the immobilized DES-ovalbumin on polystyrene microtitration plates to bind to anti-DES antibodies on DC-AuNPs, and the europium(III)-labeled streptavidin was added to link to the SH-dsDNA-biotin as a tracer. Fluorescence signal was amplified via the AuNPs and the biotin-streptavidin double amplification systems. Under the optimized condition, DES can be quantified by TRFIA. The linear range and the limit of detection of DES were 1.0×10(-6)-10ngmL(-1) and 0.4fgmL(-1), respectively. This method was applied to determine DES in beef sample, with the recoveries ranging from 88% to 105%.

Effects of prenatal morphine exposure on rat heterotypical sexual behavior

Prenatal exposure to morphine inhibits ovarian steroid-dependent lordosis behavior in female rats, and enhances certain components of male sexual behavior in male rats. In the present study, the effects of mid to late gestational morphine exposure on male sexual behavior in females and on female sexual behavior in males were examined in adult offspring. Gonadectomized male rats were injected at weekly intervals with 30 or 60 microg estradiol benzoate and 1.0 mg progesterone and tested for female sexual behavior with stimulus males on 2 consecutive weekly tests. Ovariohysterectomized (OVX) females were injected with 500 microg testosterone propionate (TP) daily for 15 days and tested for male sexual behavior with stimulus females on the last day of TP injection and 1 week later, after TP withdrawal. Prenatal morphine exposure increased the expression of male sexual behaviors in female rats, but it did not increase lordosis behavior in male rats. Thus, exposure to morphine during gestation alters male and female sexual behavior in young adult animals. Because prenatal morphine exposure both defeminized and masculinized adult sexual behavior in female rats, it is possible that female brain development is more vulnerable to prenatal insult such as opiate exposure.

A comparison of the effects of three androgens on sexual differentiation in female hamsters

The effectiveness of the synthetic androgen 17 beta-hydroxy-17 alpha-methyl-estra-4,9,11-triene-3-one (R 1881), 5 alpha-dihydrotestosterone (DHT), and testosterone to suppress the development of lordotic behavior in female hamsters were compared. Selection of these three androgens was based upon their ability to identify the active agent in defeminization. While all three hormones bind with high affinity to CNS androgen receptors, R 1881 differs from DHT because it is presumably not metabolized into less potent androgens and differs from testosterone because it is presumably not metabolized into estrogen. At birth, female hamsters were given either a single injection of 100 micrograms of hormone, five daily injections of 100 micrograms of hormone, or implanted with Silicone elastomer capsules containing hormone. Controls consisted of hamsters receiving oil injections or cholesterol implants. As adults, the hamsters wee gonadectomized, injected with estradiol benzoate and progesterone and then tested for lordosis. A single injection of androgen at birth was ineffective in suppressing lordosis duration in female hamsters. Multiple injections and implants of R 1881 or testosterone inhibited the development of female sexual behavior. R 1881 administered as five daily injections or implanted for seven days caused a similar partial reduction in lordosis duration. Testosterone was more effective in inhibiting receptivity when given as implants rather than injection. No differences were observed between females receiving testosterone implants at birth and males. DHT had no appreciable effect upon the development of behavior regardless of the route of administration or the length of treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Androgen and estradiol levels in plasma and amniotic fluid of late gestational male and female hamsters: uterine position effects

Using radioimmunoassay we have measured the plasma and amniotic fluid levels of androgen and estradiol in male and female hamster fetuses nearing parturition. On Days 14 and 15 of gestation (day of birth = Day 16), plasma levels of androgen are higher in males than females while estradiol levels are equal. Amniotic fluid levels of these hormones, while lower than plasma, reflect the difference in androgen and the similarity in estradiol between sexes. Uterine position analysis on Day 14 suggests that female siblings located caudally suppress amniotic fluid androgen and elevate estradiol levels of male siblings. Comparison of Day 18 gestation male and female rat amniotic fluid androgen to Day 14 hamsters reveals that male rats are bathed in high levels of androgen. Female rats have lower levels which are not different from those of male hamsters. Female hamsters are exposed to little androgen. Relevance to behavioral sexual differentiation and the display of adult behavior is discussed.

Estrogens before birth and development of sex-related reproductive traits in the female guinea pig

Influences of estrogens on the differentiation of psychosexual traits in the female guinea pig were studied. Pregnant animals were injected intramuscularly with either 1, 2, or 3.3 micrograms estradiol benzoate (EB) or with 1 or 3 micrograms diethylstilbestrol dipropionate (DESDP). Injections were started on the 29th day of pregnancy, given daily for 6 days, and continued every other day until parturition. Female offspring were evaluated for onset of puberty, ovarian function, and lordosis and mounting behavior in adulthood. Prenatal treatment with 3 micrograms DESDP caused delayed puberty, impaired ovarian function, reduced responsiveness of lordosis to EB and P in adulthood (defeminization), augmented mounting in the absence of hormones (masculinization), and reduced responsiveness of mounting to exogenous EB and P in adulthood (defeminization). Prenatal treatment with 1 microgram DESDP produced similar but less pronounced effects. Prenatal treatment with 3.3 micrograms EB also caused a delay in puberty. However, responsiveness of lordosis to EB and P in adulthood was enhanced by treatment with either 1 or 3.3 micrograms EB prenatally. Further, neither mounting in the absence of hormones nor mounting in response to EB and P in adulthood were affected in any measurable way by any prenatal treatment with EB. These results show that estrogens can have masculinizing and defeminizing effects on sexually dimorphic reproductive traits in guinea pigs. The failure of EB to duplicate or parallel the effects of DESDP is not completely understood at this time, but it may indicate that less of the active substance reaches the target tissues following maternal and placental metabolism of EB than of DESDP.

Physiology of sexual behavior. Embryologic organization and adult activation

Recent studies suggest that sexual behavioral function should be integrated into the framework of sexual physiology as a neuroendocrine phenomenon. Evidence of embryonic neuronal induction and subsequent adult activation and functioning of sex specific circuitry is reviewed.

Fluoxymesterone and the development of sexual behavior in the golden hamster

Male hamsters castrated at birth and female hamsters were treated on postnatal Days 2-4 with 100 microgram of testosterone. 100 microgram of fluoxymesterone, or the hormone vehicle. As adults, mounting behavior and lordosis were measured following exogenous hormone treatment. Although the degree of penile or clitoral virilization did not appear to differ between testosterone- and fluoxymesterone-treated animals, behavioral differences occurred. Neonatal treatment with fluoxymesterone failed to "masculinize" or defeminize" behavior; neonatal testosterone treatment induced mounting in males and females and intromission in males. These results, along with those of others, indicate that fluoxymesterone has little or no central neural effect on sexual behavior in the hamster.

Sexual differentiation of the central nervous system

Sexual differentiation of reproductive and behavior patterns is largely effected by hormones produced by the gonads. In many higher vertebrates, an integral part of this process is the induction of permanent and essentially irreversible sex differences in central nervous function, in response to gonadal hormones secreted early in development.

Neonatal treatment of hamsters with barbiturate alters adult sexual behavior

Male and female hamsters were given 50 micrograms pentobarbital, 100 micrograms pentobarbital, or 100 micrograms d-amphetamine on postnatal Days 2-4. When tested for masculine sexual behavior in adulthood, males treated with 100 micrograms pentobarbital showed behavioral deficits when tested with testes intact as well as after castration and treatment with testosterone propionate. Deficits shown by 50 micrograms pentobarbital males were overcome by testosterone replacement. When tested for feminine sexual behavior, males treated with 50 micrograms pentobarbital showed enhanced lordotic responses whereas males treated with 100 micrograms d-amphetamine showed no differences from controls when tested for female sexual behavior or when tested for male sexual behavior. Drug treatments had no effect on adult masculine or feminine sexual behavior in neonatally treated females. The results of this study show that pentobarbital can inhibit normal masculinization of the male when given during behavioral sexual differentiation.