Identification of Endocrine Cell Populations Expressing the AT1BSubtype of Angiotensin II Receptors in the Anterior Pituitary

Lenkei, Zsolt; Nuyt, Anne Monique; Grouselle, Dominique; Corvol, Pierre; Llorens‐Cortés, Catherine

doi:10.1210/endo.140.1.6397

Cited by 19 publications

(3 citation statements)

References 28 publications

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“…This confirms previous reports [30, 31, 48]of predominant, if not exclusive, expression of AT 1B receptors in the anterior pituitary of adult rats.…”

Section: Discussionsupporting

confidence: 93%

“…Conversely, AT 1A mRNA expression, undetectable in control nonstressed rats, was clearly detectable not only after acute restraint but after repeated restraint as well. In adult rats, AT 1B receptors are predominantly expressed in lactotrophs, and only to a minor extent in corticotrophs [48]. Because of the very low expression of AT 1A receptors in adult, nonstressed rats, their precise cellular localization in the anterior pituitary of adult rats has not been determined [48].…”

Section: Discussionmentioning

confidence: 99%

“…In adult rats, AT 1B receptors are predominantly expressed in lactotrophs, and only to a minor extent in corticotrophs [48]. Because of the very low expression of AT 1A receptors in adult, nonstressed rats, their precise cellular localization in the anterior pituitary of adult rats has not been determined [48]. We have not studied the cellular localization of AT 1A receptors that we report upregulated during stress.…”

Section: Discussionmentioning

confidence: 99%

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Restraint Stress Modulates Brain, Pituitary and Adrenal Expression of Angiotensin II AT1A, AT1B and AT2 Receptors

et al. 2002

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Angiotensin II (Ang II) AT₁ receptors are involved in the regulation of the stress response. In adult male rats, acute restraint increased AT_1A mRNA in paraventricular nucleus. Repeated restraint increased AT_1A mRNA and AT₁ binding in paraventricular nucleus and AT₁ binding in subfornical organ and median eminence. AT_1B and AT₂ receptors were not expressed in brain areas involved in the stress response. Acute restraint increased anterior pituitary AT_1A mRNA and AT₁ binding and decreased AT_1B mRNA. During repeated restraint, the increase in AT_1A mRNA in the anterior pituitary was maintained, but AT_1B mRNA and AT₁ binding returned to normal levels. In adrenal zona glomerulosa, AT_1B mRNA, AT₁ binding, AT₂ mRNA and AT₂ binding decreased during acute restraint. Receptor mRNA and binding returned to normal after repeated stress, with the exception of rebound increase in adrenal zona glomerulosa AT₂ mRNA. In adrenal medulla, AT_1A mRNA increased and AT₂ mRNA decreased during acute restraint. AT_1A mRNA remained increased during repeated restraint, while alterations in AT₂ mRNA were no longer present. Expression of AT_1A, AT_1B and AT₂ receptors in the hypothalamic-pituitary-adrenal axis is tissue specific and is different in acute and repeated stress. Increased brain, pituitary and adrenomedullary AT_1A receptor expression correlates with hypothalamic-pituitary-adrenal axis stimulation, supporting the hypothesis of Ang II, through selective AT_1A receptor stimulation, as an important determinant of the acute and repeated stress response. Decreased adrenal zona glomerulosa and anterior pituitary AT_1B receptors during acute stress can be interpreted as compensatory to increased stimulation by Ang II. There may be additional roles for adrenal AT₂ receptors during acute stress, possibly related to interaction or cross-talk with AT₁ receptors.

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“…This confirms previous reports [30, 31, 48]of predominant, if not exclusive, expression of AT 1B receptors in the anterior pituitary of adult rats.…”

Section: Discussionsupporting

confidence: 93%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Restraint Stress Modulates Brain, Pituitary and Adrenal Expression of Angiotensin II AT1A, AT1B and AT2 Receptors

et al. 2002

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Ontogeny of angiotensin II type 1 receptor mRNAs in fetal and neonatal rat brain

Nuyt

Lenkei

Corvol

et al. 2001

J of Comparative Neurology

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Studies have demonstrated a specific function of the angiotensin II (Ang II) type 1 receptor (AT(1)) in regulation of adult central cardiovascular, fluid, and pituitary hormone release and a predominant role of the renin-angiotensin system in fetal and neonatal cardiovascular homeostasis. The pattern of brain AT(1) mRNA expression during fetal and neonatal development is currently unknown. We used radiolabeled cRNA probes for in situ hybridization histochemistry to determine the ontogenic development of the two AT(1) subtypes (AT(1a) and AT(1b)) mRNA in rat brain, from 11 days of gestation (E11) to 28 days after birth (P28). No AT(1b) mRNA was detected in the developing brain, whereas AT(1a) mRNA was first detected at E19. The age at which AT(1a) mRNA is first detected varied among different brain areas and expression predominates in areas involved in fluid homeostasis, pituitary hormone release, and cardiovascular regulation, where it persists until P28. AT(1a) mRNA expression is present from E19 onward in the median preoptic nucleus, the vascular organ of the lamina terminalis, the paraventricular nucleus, the periaqueductal gray, the nucleus raphe pallidus, the motor facial nucleus, and very weakly in the nucleus of the solitary tract and the ambiguous nucleus, and at E21 in the subfornical organ, the anterior olfactory nucleus and the piriform cortex. AT(1a) mRNA expression is present after birth in many regions, including the preoptic and lateral hypothalamic areas, the area postrema and medullary reticular nuclei. In conclusion, during brain development, expression of AT(1a) mRNA, appears in late gestation at E19, predominantly in forebrain areas involved in fluid homeostasis and cardiovascular regulation. In contrast, AT(1a) mRNA expression is absent or present only in very small amounts until after birth in many medullary nuclei, known to play an important role in cardiovascular modulation. Our results suggest that, in perinatal life, AT(1a) is involved in fluid and perhaps cardiovascular homeostasis and that the role of Ang II in modulating medullary cardiovascular centers matures later in postnatal life.

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Cellular and functional interactions between gonadotrophs and lactotrophs in pituitary cell cultures

Paul

Bonaterra

Aoki

et al. 2000

Medical Electron Microscopy

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Lactotroph secretory activity is regulated by hypothalamic stimulating and inhibiting factors as well as peripheral endocrine hormones. In addition to this important control domain, the pituitary gland displays an intrinsic regulatory ability through autocrine and paracrine signals. To evaluate the role of gonadotrophs in the regulation of prolactin (PRL) secretion, a comparative study was performed applying two regulatory agents that operate through different physiological mechanisms: gonadotropin-releasing hormone (GnRH), which releases regulatory factors co-localized in secretory granules of gonadotrophs, stimulating PRL secretion from lactotrophs; and angiotensin II (AII), with direct effects on lactotroph secretion through specific receptors. In these studies performed in regular and purified primary pituitary cell cultures from female rats, the lactotrophs comprised the largest population of cells (about 51%), whereas gonadotrophs represented only a small fraction (3%) of the total pituitary cell count. In regular cell cultures treatments with AII and GnRH showed a similar secretory behavior, increasing PRL output 73% and 63%, respectively. The stimulation with GnRH and AII of cell cultures with purified lactotrophs and gonadotrophs provided comparable results, but the response of lactotrophs was significantly higher (106% and 138%, respectively) than that recorded in regular cell cultures. Simultaneous AII treatment with an antipeptide antagonist to AII receptor (AII-antipep) completely blocked the PRL release induced by AII. The co-incubation of cells with GnRH and AII-antipep suppressed the peak of PRL release caused by GnRH, confirming that AII is a paracrine agent released by gonadotrophs stimulated with GnRH. The different secretory behavior of lactotrophs treated with AII and GnRH in both regular and purified cell cultures is indicative of the degree of functional interactions between different pituitary cell types. The present study supplies morphological and functional information on the cell-to-cell interactions, which plays an important role in the intrinsic regulatory control of PRL secretion.

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Identification of Endocrine Cell Populations Expressing the AT_1BSubtype of Angiotensin II Receptors in the Anterior Pituitary

Cited by 19 publications

References 28 publications

Restraint Stress Modulates Brain, Pituitary and Adrenal Expression of Angiotensin II AT<sub>1A</sub>, AT<sub>1B</sub> and AT<sub>2</sub> Receptors

Restraint Stress Modulates Brain, Pituitary and Adrenal Expression of Angiotensin II AT<sub>1A</sub>, AT<sub>1B</sub> and AT<sub>2</sub> Receptors

Ontogeny of angiotensin II type 1 receptor mRNAs in fetal and neonatal rat brain

Cellular and functional interactions between gonadotrophs and lactotrophs in pituitary cell cultures

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