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Results for “Sexual Development”

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At least 1,189 records · Page 66Linked to original sources
PubMed1993

Effects of estradiol on the development of sexual dimorphism in the bed nucleus of the accessory olfactory tract in the rat.

Orchidectomized males injected with a single dose of estradiol benzoate (EB) on the day of birth (D1) showed a volume and neuron number in the nucleus of the accessory olfactory tract (BAOT) similar to that of control males. However, orchidectomized males and those orchidectomized and given a single dose of DHT on D1 showed a decrease in BAOT volume and neuron number with respect to control males. These results support the notion that estradiol induces the morphological masculinization of this structure. The inability of DHT in counteracting the effect of orchidectomy is addressed taking into account the inhibitory action of androgens.

Animals↗
PubMed1984

Development of sexual behavior in prenatally ethanol-exposed rats.

Female rats were given 16% ethanol solution as the sole liquid during the entire period of gestation. At birth the offspring was removed and reared by foster dams consuming normal drinking water. When tested for feminine sexual behavior in adulthood, the males showed marked signs of feminization as evidenced by an increased amount of lordosis responses. No changes were seen in the masculine sexual behavior. No deviations were seen in the female estrous cycles or in onset of vaginal estrus, whereas the onset of behavioral estrus was delayed. It is suggested that prenatal ethanol exposure may lower the fetal testosterone production and thereby interfere with the normal course of sexual differentiation in the male.

Animals↗
PubMed1995

Reptilian sex steroid receptors: amplification, sequence and expression analysis.

Sex steroid hormones secreted by the gonads play a central role in the reproduction of all vertebrates. In addition to direct effects on gametogenesis, sex steroid hormones are important in sexual development, brain organization, and sexual behavior. The actions of sex steroid hormones are mediated primarily by ligand-dependent transcription factors, or receptors which bind to specific sequences of the DNA and alter the transcription rates of nearby genes. We have used the polymerase chain reaction to amplify cDNA fragments of the estrogen receptor, progesterone receptor and androgen receptor from the unisexual whiptail lizard, Cnemidophorus uniparens. The lizard steroid hormone receptors share a high degree of sequence homology to the steroid hormone receptors of other vertebrates. Ribonuclease protection assays demonstrate that both estrogen receptor mRNA and progesterone receptor mRNA are increased in the oviduct during vitellogenesis and after estrogen treatment. This report demonstrates the utility of the polymerase chain reaction to generate species specific probes for comparative molecular studies and provides the first report of cDNA sequences for reptilian steroid hormone receptors.

Amino Acid Sequence↗
PubMed2005

The timing of changes in girls' sexual cognitions and behaviors in early adolescence: a prospective, cohort study.

PURPOSE: This small, prospective cohort study of 162 12- to 15-year-old girls examines timing of changes in sexual cognitions and behaviors (breast fondling, genital contact, and sexual intercourse) over a 1-year period. METHODS: Girls from community sites in New York City provided information about sexual experiences and related cognitions (arousability, sexual agency, abstinence attitudes, perceived parental and peer approval, and sexual self-esteem) in 2 interviews 1 year apart. RESULTS: Percentages who reported breast fondling, genital contact, and sexual intercourse (18%, 24%, and 6%) increased significantly over the year (42%, 44%, and 19%) and with age. For each behavior, analyses compared girls who did not report the behavior at either Time 1 or 2, those who reported by Time 2 but not 1, or those who reported at both time points. Girls with no breast fondling experience at either time point had stronger abstinence values, and lower arousability, agency, peer approval, and sexual self-esteem scores compared to girls who initiated breast fondling over the year (transitioners). Transitioners were markedly similar in sexual cognitions to girls with this experience before Time 1, suggesting that changes in sexual cognitions precede actual experience. A similar pattern was found between groups for genital contact. Few differences between groups by comparison were noted for sexual intercourse, which occurs later in the trajectory. CONCLUSIONS: Sexual experiences that occur before intercourse (e.g., breast fondling) are central to research on sexual development and related to greater changes in girls' sexual cognitions than is intercourse. Changes in cognitions precede, rather than follow, new sexual experiences.

Adolescent↗
PubMed2000

Gene expressions during the development and sexual differentiation of the olfactory bulb in rats.

In this study, expressions of cell-cycle-related genes: p53, retinoblastoma (Rb), p21, bcl-2(alpha), bcl-2(beta); protooncogene c-ski; glial cell marker protein gene S100beta; neurotransmitter gene, substance P and sexual-differentiation-related genes, androgen receptor (AR) and estrogen receptor beta (ER(beta)), are studied in the olfactory bulb of groups of both six female and six male rats at the ages of 3, 10, 20 and 40 days. Expressions of housekeeping genes such as beta-actin, cyclophilin and proliferating cell nuclear antigens (PCNA) are determined using reverse transcription polymerase chain reaction (RT-PCR) for the correction of unequal amount of cDNA added into the samples. Using labeled 32P-dCTP and Phosphorimager technology, relative abundance of radioactivities of the PCR products is obtained by dividing the radioactivity of each individual sample by the corresponding radioactivities of different housekeeping genes. Data evaluated by Two-way ANOVA indicate that only the bcl-2(alpha) gene expression is affected significantly by age, sex and their interactions no matter which of the three housekeeping genes is used for correction. When beta-actin was used for corrections, effects of age but not sex were found in the expressions of p53, Rb, p21, AR, ER(beta), substance P and S100beta genes, but not in bcl-2(beta), c-ski, cyclophilin and PCNA genes. While cyclophilin was used for corrections, only the p53, Rb, AR, ER(beta), substance P and S100beta but not the bcl-2(beta), p21, c-ski, PCNA and beta-actin genes are affected by age. They are all not influenced by sex of the animals. Only the AR, ER(beta) and S100beta genes are age-dependent when PCNA was used for the correction. The other gene expressions are not altered by sex, while the interactions of age and sex were found to be significantly affecting the bcl-2(beta) gene expression. Conclusively, developmental changes of the p53, Rb, AR, ER(beta), substance P and S100beta genes expressions are quite evidenced while only the bcl-2(alpha) gene seems to change significantly during the sexual differentiation of olfactory bulb in rats.

Actins↗
PubMed1997

Cloning of the entire COWP gene of Cryptosporidium parvum and ultrastructural localization of the protein during sexual parasite development.

Molecular cloning and immunoelectron microscopy have been used to clone the full-length gene encoding Cryptosporidium parvum oocyst wall protein (COWP) and to analyse at the ultrastructural level the expression and localization of COWP during development in the gut. COWP is 1622 amino acids long, has a typical leader peptide and consists of 2 amino acidic domains each containing distinct repeated elements possibly originating from a common ancestral precursor. Electron microscopy localized COWP in a large cytoplasmic inclusion and in the wall-forming bodies of early and late macrogametes, respectively. Ultrastructural analysis of double-walled sporulating and mature oocysts indicated that COWP is selectively localized in the inner layer of the oocyst wall. This study provides the first localization at the ultrastructural level of a cloned coccidian oocyst wall protein.

Amino Acid Sequence↗
PubMed2001

Role of adrenal medulla in development of sexual dimorphism in inflammation.

Many inflammatory diseases show a female predilection in adults, but not prepubertally. Because sex differences in the inflammatory response in the adult rat are mediated, in part, by sexual dimorphism in adrenal medullary function, we investigated the contribution of the adrenal medulla to the ontogeny of sexual dimorphism in inflammation. Whilst there was no sex difference in the magnitude of the plasma extravasation (PE) induced by the potent inflammatory mediator bradykinin (BK) in prepubertal rats, in adult rats BK-induced PE was markedly greater in males. Also, adult male rats, gonadectomized prior to puberty, had a lower magnitude of BK-induced PE than did adult male controls, whilst adult females gonadectomized prepubertally had higher BK-induced PE than did controls. In rats gonadectomized after puberty, the magnitude of BK-induced PE in adult males was not affected, whilst in females it resulted in significantly higher BK-induced PE, similar to the effect of prepubertal gonadectomy. When tested prepubertally, adrenal denervation increased the magnitude of BK-induced PE in females, but not in males. In contrast, in both males and females tested as adults, but castrated prepubertally, and in gonad-intact adult females, adrenal denervation significantly increased the magnitude of BK-induced PE. Adrenal denervation in prepubertal females given adult levels of 17beta-oestradiol produced a marked enhancement in the denervation-induced increase in magnitude of BK-induced PE compared to females not exposed prematurely to sex hormones. These studies suggest that an adrenal medulla-dependent inhibition of BK-induced PE is present in female but not male rats, and is enhanced by oestrogen but suppressed by testosterone.

Adrenal Medulla↗
PubMed2002

Wired for reproduction: organization and development of sexually dimorphic circuits in the mammalian forebrain.

Mammalian reproduction depends on the coordinated expression of behavior with precisely timed physiological events that are fundamentally different in males and females. An improved understanding of the neuroanatomical relationships between sexually dimorphic parts of the forebrain has contributed to a significant paradigm shift in how functional neural systems are approached experimentally. This review focuses on the organization of interconnected limbic-hypothalamic pathways that participate in the neural control of reproduction and summarizes what is known about the developmental neurobiology of these pathways. Sex steroid hormones such as estrogen and testosterone have much in common with neurotrophins and regulate cell death, neuronal migration, neurogenesis, and neurotransmitter plasticity. In addition, these hormones direct formation of sexually dimorphic circuits by influencing axonal guidance and synaptogenesis. The signaling events underlying the developmental activities of sex steroids involve interactions between nuclear hormone receptors and other transcriptional regulators, as well as interactions at multiple levels with neurotrophin and neurotransmitter signal transduction pathways.

Animals↗
PubMed1987

Retinoids in disorders of keratinization: their use in children.

During the last 10 years we treated 39 children with severe keratinization disorders with the aromatic retinoid etretinate. Six of these children were followed-up for 8-9 years. Mucocutaneous serum enzymatic and lipid side effects of etretinate were mild, transient and well tolerated. Osseous side effects were present after 4-6 years in all our 6 patients on prolonged retinoid therapy. Asymptomatic osseous neoformation and osseous reabsorption in the absence of calcium, phosphate, and alkaline phosphatase serum alterations have been observed. The growth and development curves and the sexual development of our patients (with exception of a patient with Rud's syndrome) have been normal. Osteoporosis and slender diaphysis were often present at initiation of therapy. On the basis of our findings and recent reports of the literature we suggest restricting retinoid therapy of keratinizing disorders in children to conditions severe enough to be physically, psychologically or socially incapacitating. In an attempt to reduce the risk of chronic toxicity and possibly to allow regression of initial bone alterations, intermittent therapy and combination therapy are recommended.

Adolescent↗