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Monday, July 27, 2020 | History

2 edition of Estrogen regulation of pituitary function in the gonadectomized sheep found in the catalog.

Estrogen regulation of pituitary function in the gonadectomized sheep

Gordon Jay Cooper

Estrogen regulation of pituitary function in the gonadectomized sheep

by Gordon Jay Cooper

  • 123 Want to read
  • 9 Currently reading

Published .
Written in English

    Subjects:
  • Pituitary hormones.,
  • Estrogen -- Physiological effect.

  • Edition Notes

    Statementby Gordon Jay Cooper.
    The Physical Object
    Pagination[10], 90 leaves, bound ;
    Number of Pages90
    ID Numbers
    Open LibraryOL14254166M

    We tested the hypothesis that there are sex differences in the inhibitory effect of cortisol on pulsatile LH secretion and pituitary responsiveness to GnRH in gonadectomized sheep. As the cortisol carries out many of its functions including the regulation of the immune system, the liver slowly, in a 24 hour period breaks down the cortisol for the kidneys to excrete. As the levels of regulatory cortisol decline, a signal is sent to the hypothalamic pituitary axis for the pituitary .

    The sheep is an important long-gestation animal model for understanding how sex differences in the central nervous system (CNS) develop and act to determine the sexually dimorphic control of gonadotropin secretion and sexual behaviors in the adult (1, 2).Current theories of sexual differentiation posit that testosterone secreted by the developing testis interacts with genetic factors and the.   this is the "master" gland of your endocrine system. it uses information it gets from your brain to "tell" other glands in your body what to do.

    In gonadectomized sheep, regardless of sex, the negative feedback of exogenous estradiol is most profound during the anestrous season. The effect of photoperiod on secretion of gonadotropins may reflect a seasonal shift in the sensitivity of the hypothalamus or other neural centers to estradiol [7]. In: Beck-Peccoz P (ed) Regulation of Pituitary Hormone Secretion, HypoCCS Series, Vol. 3. BioScientifica Ltd, Bristol, pp 85 –95 Simpson ER, Mahendroo MS, Means GD, Kilgore MW, Hinshelwood MM, Graham-Lorence S, Amarneh B, Ito Y, Fisher CR, Michael MD () Aromatase cytochrome P, the enzyme responsible for estrogen biosynthesis.


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Estrogen regulation of pituitary function in the gonadectomized sheep by Gordon Jay Cooper Download PDF EPUB FB2

A total of five individual experiments were conducted with gonadectomized, male sheep to study the influence of estrogen on the plasma level of pituitary activities, with the greatest emphasis given to gonadotropic activity. Estrogen treatments employed were as follows: 1.

12 mg. diethylstilbestrol (DES) implanted subcutaneously. : Gordon Jay Cooper. Estrogen regulation of pituitary function in the gonadectomized sheep. Abstract. Graduation date: A total of five individual experiments were conducted with\ud gonadectomized, male sheep to study the influence of estrogen on\ud the plasma level of pituitary activities, with the greatest emphasis\ud given to gonadotropic activity.

Estrogen and HPG Axis in Males: Lessons from Animal Models. The development of knock-out or transgenic mice with targeted disruptions of ERs and/or aromatase has increased our understanding of estrogen function in reproduction ().Controversy aspect regarding the male hypothalamic and pituitary feedback regulation by steroids has been partially resolved by the Cited by:   The genomic actions of estrogen are mediated by two distinct intracellular receptors that function as ligand-activated transcription factors.

These have been termed estrogen receptor alpha (ERα) and beta (ERβ) (Green et al.,Kuiper et al., ).For both forms of ER, the binding of estrogen results in receptor dimerization, binding to specific DNA sites in gene promoter regions Cited by:   The low dose of E2B was chosen because our previous studies demonstrated that estrogenic effects on the expression pattern of pituitary and uterine estrogen-sensitive genes were observed in mature gonadectomized female rats, and circulating E2 levels were within the physiological range observed during a regular estrus cycle.Cited by: 5.

estrogenic regulation of prolactin synthesis in sheep Experimental evidence implicating estradiol in the regulation of prolactin secretion in sheep is rather limited. There is a preovulatory surge of prolactin, with plasma concentrations ranging from 10–40 ng/ml to 40–50 ng/ml throughout the estrous cycle (Reeves and colleagues,   The anterior pituitary is derived from oral ectoderm and, typical of an endocrine gland, has cells grouped in cords and follicles.

Approximately 50% of the cells are somatotrophs that produce GH ().These cells are primarily located in the lateral wings of the anterior lobe, but can also be scattered in the median tin (PRL)-secreting lactotrophs represent ~15% of cells in the.

Pituitary hyperplasia and lactotroph replication are induced by estrogen. The product of the pituitary tumor transforming gene (PTTG) exhibits in vitro and in vivo transforming activity and induces basic bFGF secretion, thereby modulating pituitary angiogenesis and tumor demonstrated previously that pituitary pttg is induced by estrogen and bFGF, the latter being.

ellington ef, contopoulos an, clegg mt. progesterone regulation of the production and release of pituitary gonadotrophins in the gonadectomized sheep. endocrinology. sep; – elrick h, yearwood-drayton v, arai y, morris hg. hormonal content of human pituitaries from embalmed bodies.

j clin endocrinol metab. sep; – 3. The reproductive neuroendocrine axis in postmenopausal women. By the time of the postmenopausal period, the degeneration of ovarian follicles is complete and circulating estrogen and progesterone are reduced to castrate levels [4,9,66,].The profound deficiency in ovarian hormones results in elevated levels of serum gonadotropins due to the removal of steroid negative feedback and loss of.

Moreover, it appears that this action of estradiol is elicited at the pituitary and/or the hypothalamus that has been shown to drive pituitary lactotroph function in the sheep and rodent fetus. Thus, in the current study fetal prolactin levels and expression by the pituitary were markedly reduced in estrogen-suppressed animals and only.

AN ABSTRACT OF THE THESIS OF Animal Science Gordon Jay Cooper for the M. it (Physiology) (Name) (Degree) (Major) Date thesis is presented September 2, Title ESTROGEN REGUL. AR and ERα are located in the nuclei and this distribution pattern of AR and ERα in anterior pituitary of the sheep lamb is the same as those that in the developing pituitary gland of sheep fetus (Yuan et al., ).

Expression of AR and ERα reflects the functional status of androgen and estrogen in pituitary. Time of neuroendocrine puberty and estradiol positive feedback response in gonadectomized, estrogen-treated male, female, and androgenized female Poll Dorset sheep.

The majority of studies of sexual differentiation of reproductive neuroendocrine function have been performed in Suffolk or Suffolk cross-bred sheep in which the timing of puberty. We tested the hypothesis that there are sex differences in the inhibitory effect of cortisol on pulsatile LH secretion and pituitary responsiveness to GnRH in gonadectomized sheep.

In experiment 1, pulsatile LH secretion was examined in gonadectomized ewes and rams infused with either saline, a low ( μg/kgh) or a high ( μg/kgh) dose. Please use one of the following formats to cite this article in your essay, paper or report: APA.

Dutta, Sanchari Sinha. (, December 18). Pituitary Gland Hormones and Functions. Estrogen is an important component of fetal neuroendocrine function in late-gestation fetal sheep; however, little is known about the regulation of estrogen receptor abundance in the brain and.

The pituitary gland is a part of your endocrine system. Its main function is to secrete hormones into your bloodstream. These hormones can affect other organs and glands, especially your. However, genetic regulation of estrogen-induced pituitary growth has been less well characterized in mice than rats.

In one study, Gardner and Strong (31) presented a comparison of pituitary responses in seven different mouse strains (A, C 3 H, CBA, C12I, JK, N, and C57). ARC, estrogen and testosterone inhibit the expression of Kiss1,whereasintheAVPV,thesesamesteroidsstimulate Kiss1 expression (Figure 1) [30,31,33,34].

Similarly, in gonadectomized rodents (i.e. having very low sex steroids), levels of Kiss1 mRNA are increased in the ARC and decreased in the AVPV [30,31,33,34]. The differential Figure 1. The pituitary gland is a tiny organ, the size of a pea, found at the base of the brain.

As the “master gland” of the body, it produces many hormones that travel throughout the body, directing certain processes or stimulating other glands to produce other pituitary gland makes or. Obesity and some liver diseases can lower SHBG and thus total estrogen levels.

Fertility is a complicated topic. Suffice it to say that normal regular menses and an appropriate rise in basal body temperature 14 days before menses indicate normal function of the hypothalamic-pituitary-ovarian-uterine axis.

Studies should be done to check for.Abstract. Estradiol has been demonstrated to affect the production or release of all six major anterior pituitary hormones (1–5).

Although some of the effects of estradiol on hormonal secretion are primarily hypothalamic in nature, other physiologically relevant actions appear to occur directly within the anterior pituitary gland itself (6–9).