Intercellular interactions in the anterior pituitary

Schwartz, Jeffrey; Perez, Franck

doi:10.1007/bf03347740

Cited by 12 publications

(4 citation statements)

References 121 publications

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“…It is now widely accepted that the anterior lobe of the pituitary gland has an intrinsic regulatory capacity through paracrine and autocrine signals and that this type of regulation can robustly affect lactotroph function (141,1577). Because these local regulatory mechanisms of the pituitary gland have recently been extensively reviewed (141,(1577)(1578)(1579), we will provide only a brief survey of local control of prolactin secretion and elaborate on recent developments in this quickly expanding research area. Modes of local regulation of cellular functions, brought about by the secretion of diffusible molecules, can be further divided based on the positional relation of the participating cells.…”

Section: B Intrapituitary Regulationmentioning

confidence: 99%

Hypothalamic Prolactin Receptor Messenger Ribonucleic Acid Levels, Prolactin Signaling, and Hyperprolactinemic Inhibition of Pulsatile Luteinizing Hormone Secretion Are Dependent on Estradiol

et al. 2007

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Hyperprolactinemia can reduce fertility and libido. Although central prolactin actions are thought to contribute to this, the mechanisms are poorly understood. We first tested whether chronic hyperprolactinemia inhibited two neuroendocrine parameters necessary for female fertility: pulsatile LH secretion and the estrogen-induced LH surge. Chronic hyperprolactinemia induced by the dopamine antagonist sulpiride caused a 40% reduction LH pulse frequency in ovariectomized rats, but only in the presence of chronic low levels of estradiol. Sulpiride did not affect the magnitude of a steroid-induced LH surge or the percentage of GnRH neurons activated during the surge. Estradiol is known to influence expression of the long form of prolactin receptors (PRL-R) and components of prolactin's signaling pathway. To test the hypothesis that estrogen increases PRL-R expression and sensitivity to prolactin, we next demonstrated that estradiol greatly augments prolactin-induced STAT5 activation. Lastly, we measured PRL-R and suppressor of cytokine signaling (SOCS-1 and -3 and CIS, which reflect the level of prolactin signaling) mRNAs in response to sulpiride and estradiol. Sulpiride induced only SOCS-1 in the medial preoptic area, where GnRH neurons are regulated, but in the arcuate nucleus and choroid plexus, PRL-R, SOCS-3, and CIS mRNA levels were also induced. Estradiol enhanced these effects on SOCS-3 and CIS. Interestingly, estradiol also induced PRL-R, SOCS-3, and CIS mRNA levels independently. These data show that GnRH pulse frequency is inhibited by chronic hyperprolactinemia in a steroid-dependent manner. They also provide evidence for estradiol-dependent and brain region-specific regulation of PRL-R expression and signaling responses by prolactin.

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Section: B Intrapituitary Regulationmentioning

confidence: 99%

Hypothalamic Prolactin Receptor Messenger Ribonucleic Acid Levels, Prolactin Signaling, and Hyperprolactinemic Inhibition of Pulsatile Luteinizing Hormone Secretion Are Dependent on Estradiol

et al. 2007

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“…Paracrine and autocrine interactions within the anterior pituitary have engendered an increasing interest, as attested by several recent reviews (1,3,21). The anterior pituitary has been found to harbor, apart from classical adenohypophyseal hormones, several other peptides which participate in cell-tocell interactions and modulate hormonal secretion (2).…”

Section: Discussionmentioning

confidence: 99%

Corticotropin-releasing hormone is produced by rat corticotropes and modulates ACTH secretion in a paracrine/autocrine fashion.

Giraldi¹,

Cavagnini²

1998

J. Clin. Invest.

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Anterior pituitary hormone secretion is mainly regulated by hypothalamic releasing factors, which reach the pituitary via portal vessels. It has been demonstrated recently that these peptides can also be produced by the pituitary itself, thus possibly modulating hormone secretion in a paracrine/ autocrine fashion. The object of this study was to seek evidence for the synthesis and secretion of corticotropin-releasing hormone (CRH) within the anterior pituitary and to ascertain its biological relevance. Messenger RNA from adult rat anterior pituitary fragments and cell cultures was reverse transcribed and subjected to PCR amplification using primers specific to the rat CRH gene. As in the hypothalamus, a single 232-bp band was obtained. The correspondence of the amplified fragment to the sequence of the

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“…Paracrine, autocrine and direct membrane-to-membrane mechanisms have an important role in anterior pituitary function [1, 2, 3, 4, 5]. Dispersed cell culture is widely used to study dynamic anterior pituitary cell function, but there is evidence that paracrine effects may vary with cell density [6].…”

Section: Introductionmentioning

confidence: 99%

Effect of Cell Density on Hormonal Secretion from Human Pituitary Adenomas in vitro

Atkin

Hipkin²,

Landolt³

et al. 1998

Horm Res Paediatr

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Cell density effects were investigated on tumorous hormonal secretion from 10 pituitary adenomas: 3 somatotrophinomas secreting GH and PRL; 7 gonadotrophinomas, 3 co-secreted both FSH and LH, all 7 secreted LH. Enzymatically dispersed tissue was plated out in 24-well plates at 5 ×10⁵, 10⁵, 5 ×10⁴ and 10⁴ cells/well in serum-free media. Media were collected weekly for 2 weeks. Results: In 3 of 3 somatotrophinomas, GH and PRL secretion was higher (p < 0.05) at both week 1 and 2 from 10⁴ cells/well, but similar at other cell densities. In all 3 gonadotrophinomas, the FSH secretory rate was highest at 5 ×10⁵ cells/well which fell as cell density decreased. Conversely, in 7 of 7 gonadotrophinomas the LH secretory rate was highest at 10⁴ cells/well (p < 0.01) which fell as cell density increased. Conclusion: These data suggest that paracrine factors may modulate tumorous GH, PRL, FSH and LH secretion, and show that FSH and LH secretion vary inversely as cell density increases.

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Intercellular interactions in the anterior pituitary

Cited by 12 publications

References 121 publications

Hypothalamic Prolactin Receptor Messenger Ribonucleic Acid Levels, Prolactin Signaling, and Hyperprolactinemic Inhibition of Pulsatile Luteinizing Hormone Secretion Are Dependent on Estradiol

Hypothalamic Prolactin Receptor Messenger Ribonucleic Acid Levels, Prolactin Signaling, and Hyperprolactinemic Inhibition of Pulsatile Luteinizing Hormone Secretion Are Dependent on Estradiol

Corticotropin-releasing hormone is produced by rat corticotropes and modulates ACTH secretion in a paracrine/autocrine fashion.

Effect of Cell Density on Hormonal Secretion from Human Pituitary Adenomas in vitro

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