Functional grafts of the anterior pituitary gland

Harris, G. W.; Jacobsohn, Dora

doi:10.1098/rspb.1952.0011

Cited by 248 publications

(28 citation statements)

References 12 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…He inferred that the anterior pituitary gland is the site of the dimorphism resulting from the perinatal action of testicular hormones in the male. It was much later than Harris and Jacobsohn (78) established that the hypothalamus, and not the pituitary gland itself, is primarily responsible for the sex dimorphism in the preovulatory release of gonadotrophins. Pituitary glands taken from adult male rats were able to support cyclic ovarian activity when transplanted under the median eminence of hypophysectomized female rats.…”

Section: Patterns Of Lh Secretionmentioning

confidence: 99%

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

Baum

Carroll

Cherrv

et al. 1990

J Neuroendocrinology

View full text Add to dashboard Cite

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...

show abstract

Section: Patterns Of Lh Secretionmentioning

confidence: 99%

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

Baum

Carroll

Cherrv

et al. 1990

J Neuroendocrinology

View full text Add to dashboard Cite

show abstract

“…Among spontaneously ovulating species, sex dimorphisms in the occurrence of preovulatory LH secretion have been studied most extensively in the laboratory rat (89,161,173). A preovulatory LH surge could be induced in female, …”

Section: Sex Differences In Gnrh Secretionmentioning

confidence: 99%

“…Gonadectomized male and female ferrets (32) showed similar LH responses to exogenous GnRH treatment, regardless of whether they were tested with or without concurrent estradiol treatment. More recently, Yang et al (247) provided direct evidence for the absence of a coitus-induced surge in MBH release of GnRH as well as in plasma LH in the male rabbit.Among spontaneously ovulating species, sex dimorphisms in the occurrence of preovulatory LH secretion have been studied most extensively in the laboratory rat (89,161,173). A preovulatory LH surge could be induced in female, …”

mentioning

confidence: 99%

Neuroendocrine Regulation of GnRH Release in Induced Ovulators

Bakker

Baum

2000

Frontiers in Neuroendocrinology

180

135

View full text Add to dashboard Cite

GnRH is the key neuropeptide controlling reproductive function in all vertebrate species. Two different neuroendocrine mechanisms have evolved among female mammals to regulate the mediobasal hypothalamic (MBH) release of GnRH leading to the preovulatory secretion of LH by the anterior pituitary gland. In females of spontaneously ovulating species, including rats, mice, guinea pigs, sheep, monkeys, and women, ovarian steroids secreted by maturing ovarian follicles induce a pulsatile pattern of GnRH release in the median eminence that, in turn, stimulates a preovulatory LH surge. In females of induced ovulating species, including rabbits, ferrets, cats, and camels, the preovulatory release of GnRH, and the resultant preovulatory LH surge, is induced by the receipt of genital somatosensory stimuli during mating. Induced ovulators generally do not show "spontaneous" steroid-induced LH surges during their reproductive cycles, suggesting that the positive feedback actions of steroid hormones on GnRH release are reduced or absent in these species. By contrast, mating-induced preovulatory surges occasionally occur in some spontaneously ovulating species. Most research in the field of GnRH neurobiology has been performed using spontaneous ovulators including rat, guinea pig, sheep, and rhesus monkey. This review summarizes the literature concerning the neuroendocrine mechanisms controlling GnRH biosynthesis and release in females of several induced ovulating species, and whenever possible it contrasts the results with those obtained for spontaneously ovulating species. It also considers the adaptive, evolutionary benefits and disadvantages of each type of ovulatory control mechanism. In females of induced ovulating species estradiol acts in the brain to induce aspects of proceptive and receptive sexual behavior. The primary mechanism involved in the preovulatory release of GnRH among induced ovulators involves the activation of midbrain and brainstem noradrenergic neurons in response to genital-somatosensory signals generated by receipt of an intromission from a male during mating. These noradrenergic neurons project to the MBH and, when activated, promote the release of GnRH from nerve terminals in the median eminence. In contrast to spontaneous ovulators, there is little evidence that endogenous opioid peptides normally inhibit MBH GnRH release among induced ovulators. Instead, the neural signals that induce a preovulatory LH surge in these species seem to be primarily excitatory. A complete understanding of the neuroendocrine control of ovulation will only be achieved in the future by comparative studies of several animal model systems in which mating-induced as well as spontaneous, hormonally stimulated activation of GnRH neurons drives the preovulatory LH surge. KEY WORDS: GnRH; MBH; induced ovulators; neuroendocrine regulation; preovulatory LH surge; spontaneous ovulators. © 2000 Academic Press Address correspondence and reprint requests to M. J. Baum at Dept. Biology, Boston University, 5 Cummington Street, Boston...

show abstract

“…

…”

mentioning

confidence: 99%

Ovulation induction with LH-RH in rats rendered acyclic by hypophysial grafts

Lotz¹,

Krause²

1976

Reproduction

View full text Add to dashboard Cite

That the rat hypophysis is dependent on hypothalamic support was established several decades ago by shrewd transplantation studies (Greep, 1936;Harris & Jacobsohn, 1952). An hypophysis removed from contact with the median eminence area loses the capacity to synthesize and release most of its trophic hormones. Since prolactin is controlled primarily by a factor which inhibits its release, its serum concentration is elevated in hypophysectomized rats bearing hypophysial homografts in their kidneys (Chen, Amenomori, Lu, Voogt & Meites, 1970

show abstract

Functional grafts of the anterior pituitary gland

Abstract: B y G . W . H a r r is a n d D o r a J a c o b s o h n

Cited by 248 publications

References 12 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

Neuroendocrine Regulation of GnRH Release in Induced Ovulators

Ovulation induction with LH-RH in rats rendered acyclic by hypophysial grafts

Contact Info

Product

Resources

About