Sexual Differentiation of Pituitary Function: Apparent Difference between Primates and Rodents

Karsch, Fred J.; Dierschke, Donald J.; Knobil, E.

doi:10.1126/science.179.4072.484

Cited by 181 publications

(76 citation statements)

References 22 publications

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“…The two daily injections of free oestradiol together with collection of blood at 4-h intervals were continued for 4 consecutive days. A similar paradigm has previously been used in rhesus monkeys to establish the ability of males to exhibit preovulatory LH surges (81). In the present study, however, neither male nor female ferrets exhibited the slightest elevation in plasma LH levels over the 96 h following injection of oestradiol benzoate.…”

Section: Patterns Of Lh Secretionmentioning

confidence: 56%

Steroidal Control of Behavioural, Neuroendocrine and Brain Sexual Differentiation: Studies in a Carnivore, the Ferret

Baum

Carroll

Cherrv

et al. 1990

J Neuroendocrinology

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More than 30 years have passed since the publication ( I ) showing that transplacental administration of testosterone to female guinea-pigs caused permanent changes in their ability to exhibit reproductive behaviours in response to ovarian steroids in adulthood. Over the intervening years articles have appeared which have extended this type of observation to numerous other mammalian species, including rat, hamster, gerbil, mouse, dog, ferret, pig, sheep, rhesus monkey, and marmoset (2, 3). In many instances inferences have been made about the probable existence of steroid-induced changes in the structure and function of the nervous system which underlie these changes in behaviour. These so-called 'organizational' effects of perinatal steroid exposure on the developing nervous system are often distinguished from the later 'activational' effects of these same steroids on the expression of sociosexual behaviours in adulthood. The number of different mammalian species used for mechanistic studies on the organizational effects of steroids, such as determining the precise perinatal timing of hormone action, the identity of the steroid(s) responsible for behavioural sexual differentiation, and the neural sites of steroid action, has been relatively small, and generally restricted to rodents. In the late 1970's sex steroids acting during development were first implicated in the differentiation of sexually dimorphic telencephalic structures in passerine song birds which control singing associated with courtship (4, 5). Since this early work, numerous studies have exploited the canary and zebra finch to explore mechanisms of steroid action in controlling the ontogeny of song in the male and the underlying changes in the nervous system. Other studies using the rat have explored in detail the role of androgen and oestrogen in controlling the differentiation in males of patterns of reproductive behaviour (2) as well as aspects of neural sex dimorphisms in the preoptic area/anterior hypothalamus (POA/AH) (6) and in the lumbar spinal cord (7). The concentration of mechanistic (behavioural, biochemical, neuroanatomical) studies of steroidal effects on sexually dimorphic behavioural potential in a few avian and rodent species is understandable, in light of their relative availability, low expense, and rapid time-course of neural development.Despite the substantial progress already made using these lower vertebrate models in promoting our understanding of how sex steroids influence neural and behavioural development, extrapolation of the results obtained in these studies to higher mammals including man cannot occur in the absence of some degree of empirical verification. Obviously, experimental manipulations of steroidal exposure during the development of human subjects would be unethical, thus we are left with experiments of nature (e.g. congenital adreno-genital syndrome,androgen insensitivity syndrome, and Sa-reductase deficient pseudohermaphroditism; details in later sections) with which to ask questions about the role of sex...

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Section: Patterns Of Lh Secretionmentioning

confidence: 56%

Steroidal Control of Behavioural, Neuroendocrine and Brain Sexual Differentiation: Studies in a Carnivore, the Ferret

Baum

Carroll

Cherrv

et al. 1990

J Neuroendocrinology

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“…The isolated adult rat liver regulates the activities of these two enzymes directly in response to circulating glucose concentration as well as in response to hormones (4,12,13,20). The relative physiologic contributions of glucose and hormonal regulation of glycogen metabolism in vivo are unknown.…”

Section: Discussionmentioning

confidence: 99%

“…In contrast, fetal and neonatal exposure of the brain of the rhesus monkey to gonadal steroids does not appear to influence the basic hypothalamic mechanisms controlling reproduction (4).…”

mentioning

confidence: 81%

Gonadotropin and Testosterone Measurements after Estrogen Administration to Adult Men, Prepubertal and Pubertal Boys, and Men with Hypogonadotropism: Evidence for Maturation of Positive Feedback in the Male

Kulin

Reiter

1976

Pediatr Res

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ExtractNineteen male subjects were given five daily injections of 17P-estradiol and circulating levels of estradiol (E,), testosterone (T), and gonadotropins were determined by radioimmunoassay before, during, and after the steroid course. Peak levels of E, attained during the 5 days of treatment ranged from 173-577 pg/ml. Four of seven normal adult men and one castrate man demonstrated suppression of follicle-stimulating hormone ( FSH ) and luteinizing hormone (LHI with a subseauent rise in LH (oositive feedback) while E, levels remained elevated. A rise in T ;is associated with the L H increment in the four normal men. Nine pre-, early, or midpubertal boys and two men with hypogonadotropic hypogonadism displayed only gonadotropin soppressiorl after E, administration. The difference in LH response to estrogen (i.e., positive feedback) between the adult men with normal or elevated gonadotropin levels as compared with the endocrinologically normal boys is significant ( P < 0.01 ). SpeculationPositive feedback between estrogen and 1.H is present in intact adult men, although the magnitude and consistency of this response is less than in women. Testosterone in men may act like progesterone in the female rhesus monkey to blunt the magnitude of the L H rise during estrogen administration. The potential for positive feedback appears to be a maturational event occurring during puberty in men as well as in women.Sexual differentiation of the brain and the consequent ability of the female of the species to exhibit regular ovulatory cycles exists in certain rodents and can be influenced by neonatal exposure to a number of steroid hormones. In contrast, fetal and neonatal exposure of the brain of the rhesus monkey to gonadal steroids does not appear to influence the basic hypothalamic mechanisms controlling reproduction (4).The ability of estrogen to induce the release of LH, termed positive feedback, has been demonstrated in the intact, adult female and in the postpubertal, castrate male, and female rhesus monkey (18). Such effects of estrogen have not been found in the intact, adult male rhesus. LH re!ease after estrogen administration has also been demonstrated in adult women (9, 11) but not in sexually immature girls ( I I). The onset of positive feedback appears to be a late pubertal event in the female (I I). We should like to present evidence that a stimulatory luteinizing hormone response to exogenous estrogen is also a maturational event in men. M A T E R I A L S A N D M E T H O D S SUBJECTSSeven normal, adult men (ages 20-22) and one male (age 21) with the syndrome of vanishing testes (1) were hospitalized for study at the Clinical Center of the National Institutes of Health. Each patient was given five daily intramuscular injections of 10 or 15 pg/kg body weight of 17P-estradiol (E,) (20) and blood samples were obtained every 12-24 hr before, during, and after the estrogen course (see Table 1).Nine endocrinologically normal boys between the ages of 7 and 18 were studied in the course of evaluation for short stat...

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“…A surge of prolactin, occurring at the same time as the LH surge, can also be elicited by oestrogen treatment (Cheng & Johnson, 1974) and can be shown at 9 days of age (Puig-Duran & MacKinnon, 1978). The male rat is known to be unable to respond to a steroid stimulus with a release of gonadotrophins, although such a sexually differentiated response does not seem to hold true for the monkey (Karsch, Dierschke & Knobil, 1973) or man (Steams, Winter & Faiman, 1973 Has the 'daily signal' a role to play in the onset of puberty?…”

Section: Positive Feedbackmentioning

confidence: 99%

Reflections on the attainment of puberty in the rat: have circadian signals a role to play in its onset?

Mackinnon¹,

Puig-Duran²,

Laynes³

1978

Reproduction

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Sexual Differentiation of Pituitary Function: Apparent Difference between Primates and Rodents

Cited by 181 publications

References 22 publications

Steroidal Control of Behavioural, Neuroendocrine and Brain Sexual Differentiation: Studies in a Carnivore, the Ferret

Steroidal Control of Behavioural, Neuroendocrine and Brain Sexual Differentiation: Studies in a Carnivore, the Ferret

Gonadotropin and Testosterone Measurements after Estrogen Administration to Adult Men, Prepubertal and Pubertal Boys, and Men with Hypogonadotropism: Evidence for Maturation of Positive Feedback in the Male

Reflections on the attainment of puberty in the rat: have circadian signals a role to play in its onset?

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