Hormonal Actions on the Sexual Differentiation of the Genitalia and the Gonadotropin-Regulating Systems

Feder, Harvey H.

doi:10.1007/978-1-4684-3875-8_5

Cited by 9 publications

(6 citation statements)

References 131 publications

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“…In rodents, the POA mechanism that triggers the pre-ovulatory LH surge in adult females is decommissioned in males by an action of testicular testosterone secreted during the early postnatal period of development (10). As may have been predicted from the established role of POA kisspeptin neurons in triggering the LH surge during the estrous cycle, kisspeptin expression in the POA of the mouse and rat is sexually dimorphic showing a dramatic female-dominant sex difference in the number of these peptidergic neurons (11,12).…”

Section: Introductionmentioning

confidence: 99%

Estradiol Upregulates Kisspeptin Expression in the Preoptic Area of both the Male and Female Rhesus Monkey (Macaca mulatta): Implications for the Hypothalamic Control of Ovulation in Highly Evolved Primates

Trujillo¹,

Kalil²,

Ramaswamy³

et al. 2016

Neuroendocrinology

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The aim of this immunohistochemical study was to evaluate the distribution of kisspeptin neurons in the preoptic area (POA) of gonadally intact adult male and female rhesus monkeys, and to determine whether imposition of an estradiol (E₂)-positive feedback signal in the castrate male increased kisspeptin in the POA. Additionally, kisspeptin in the POA of the intact female was examined during an LH surge induced prematurely by E₂ administered in the early follicular phase. The number of kisspeptin neurons in the POA of males and females was similar. Immunoactive kisspeptin perikarya were not observed in the POA of castrate adult males, but such neurons in these animals were present within 12 h of imposing an increment in circulating E₂ concentrations that in a screening study conducted 4-6 weeks earlier had elicited an LH surge. As expected, premature induction of an LH surge by E₂ early in the follicular phase was associated with upregulation of kisspeptin in the POA. These results represent the first description of immunoreactive kisspeptin cell bodies in the POA of the macaque brain and provide further support for the view that (1) kisspeptin neurons in the POA of the female monkey are a target for the positive feedback action of E₂ and (2) the hypothalamic mechanism which mediates this action of E₂ in primates is not subjected to perinatal programming by testicular testosterone. Moreover, our findings indicate that maintenance of the kisspeptin content in the POA of intact male monkeys requires the action of E₂, presumably generated by aromatization of testicular testosterone at the hypothalamic level.

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Section: Introductionmentioning

confidence: 99%

Estradiol Upregulates Kisspeptin Expression in the Preoptic Area of both the Male and Female Rhesus Monkey (Macaca mulatta): Implications for the Hypothalamic Control of Ovulation in Highly Evolved Primates

Trujillo¹,

Kalil²,

Ramaswamy³

et al. 2016

Neuroendocrinology

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“…The cause of this failure to ovulate has been shown to be masculinization of the LH-controlling mechanisms in the hypothalamus such that the cyclic peak of LH that normally triggers ovulation is absent, as it is in normal males (Feder, 1981a).…”

Section: Introductionmentioning

confidence: 99%

Effect of embryonic treatment with oestradiol benzoate on reproductive morphology, ovulation and oviposition and plasma LH concentrations in female quail (Coturnix coturnix japonica)

Rissman¹,

Ascenzi²,

Johnson³

et al. 1984

Reproduction

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“…First the genotype determines the production of ovaries or testes. Then differential secretion of sex hormones determines the development of male and female secondary sex characters and behavior (1)(2)(3)(4). Earlier studies of sex hormones in sexual differentiation (5)(6)(7)(8)(9)(10) assumed that in birds, in which the embryo develops in the egg outside the mother, the developing organism was the main source of sex hormones that influence development.…”

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Yolk is a source of maternal testosterone for developing birds.

Schwabl

1993

Proc. Natl. Acad. Sci. U.S.A.

759

664

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The sex steroid hormones that affect development in birds have been thought to be produced exclusively by the embryo or neonate. I used radioimmunoassay to measure the amounts of androstenedione, 5a-dihydrotestosterone, testosterone, 173-estradiol, and corticosterone in the yolk of freshly laid canary (Serinus canaria) and zebra finch (Poephilaguaata) eggs.Testosterone was found in both canary and zebra finch eggs, but its contents were much higher in the former than in the latter. The testosterone content of canary eggs in a same clutch increased with the order of laying, regardless of the genetic sex of the offspring that hatched from these eggs. Yolk testosterone was also present in the eggs of female canaries that were kept without a male, indicating that it is ofmaternal origin. The social rank of juvenile canaries was positively correlated with the concentration of yolk testosterone in the eggs from which they hatched, suggesting that the development of aggressive behavior of offspring might be subject to modification by maternal testosterone. These findings indicate that female songbirds can bestow upon their eggs a dose of hormone that modifies the behavior of offspring. Variable doses of these hormones might explain some of the individual variation in offspring behavior.Development of sex in higher vertebrates occurs in two steps. First the genotype determines the production of ovaries or testes. Then differential secretion of sex hormones determines the development of male and female secondary sex characters and behavior (1-4). Earlier studies of sex hormones in sexual differentiation (5-10) assumed that in birds, in which the embryo develops in the egg outside the mother, the developing organism was the main source of sex hormones that influence development. However, steroid hormones are lipophilic, and they may pass from the mother into the lipoprotein matrix of egg yolk during vitellogenesis. The presence of such hormones might affect developmental processes before embryonic steroidogenic tissue becomes active and could influence the fitness of offspring. That steroid hormones can pass from the female's circulation into the egg is suggested by experiments that show modification of offspring sexual differentiation in response to treatment of the egg-laying female with exogenous estradiol (11,12 removed, and a small yolk sample (10-15 mg) was obtained by inserting a 25-gauge needle through the small end of the egg into the yolk. After sealing the hole with transparent wound dressing, the eggs were returned to the nests, so that clutch size was not changed. The yolk sample was weighed, diluted with 0.5 ml of distilled water, mixed, and frozen for hormone assays. In addition, eggs from three females that were kept without a male were removed daily from the nests during the 1992 breeding season. In this case eggs were not returned to the nest, and the yolk was collected and frozen. Eggs laid at intervals of no more than 2 days were considered to belong to the same clutch.Steroid Hormone Assays. I...

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Hormonal Actions on the Sexual Differentiation of the Genitalia and the Gonadotropin-Regulating Systems

Cited by 9 publications

References 131 publications

Estradiol Upregulates Kisspeptin Expression in the Preoptic Area of both the Male and Female Rhesus Monkey <b><i>(Macaca mulatta)</i></b>: Implications for the Hypothalamic Control of Ovulation in Highly Evolved Primates

Estradiol Upregulates Kisspeptin Expression in the Preoptic Area of both the Male and Female Rhesus Monkey <b><i>(Macaca mulatta)</i></b>: Implications for the Hypothalamic Control of Ovulation in Highly Evolved Primates

Effect of embryonic treatment with oestradiol benzoate on reproductive morphology, ovulation and oviposition and plasma LH concentrations in female quail (Coturnix coturnix japonica)

Yolk is a source of maternal testosterone for developing birds.

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