Specific Receptors for Vasopressin in the Pituitary Gland: Evidence for Down-Regulation and Desensitization to Adrenocorticotropin-Releasing Factors

Koch, Bernard; Lutz-Bucher, B.

doi:10.1210/endo-116-2-671

Cited by 85 publications

(39 citation statements)

References 15 publications

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“…Finally, pituitary desensitization to AVP may occur (similar to what has been shown for CRF in in vivo animal studies) independently of any steroid feedback (45). The anterior pituitary contains specific receptors for AVP which are distinct from those for hypothalamic CRF (46,47), and prior injections of AVP might cause down-regulation of the AVP specific receptor on pituitary cells (47). To determine which, if any, of the explanations is correct will require further study.…”

Section: Discussionmentioning

confidence: 83%

Vasopressin stimulation of adrenocorticotropin hormone (ACTH) in humans. In vivo bioassay of corticotropin-releasing factor (CRF) which provides evidence for CRF mediation of the diurnal rhythm of ACTH.

Salata¹,

Jarrett²,

Verbalis³

et al. 1988

J. Clin. Invest.

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The diurnal response of ACTH release to intravenously administered arginine vasopressin was tested in normal volunteers given consecutively moderate doses of vasopressin every 15 min (0.1, 03, 1.0, and 3.0 IU) at 2200 h and again at 0700 h (PM/AM). This protocol was repeated 4 wk later with the times reversed (AM/PM). A dose-related increase in ACIH secretion was observed in all subjects. When the AM response of the AM/PM protocol was compared with the PM response of the PM/AM protocol, the release of ACTH was greater in the morning (P < 0.05) as evaluated by the following criteria: peak value of ACTH (129.9±30.4 pg/ml in the AM vs. 57.1±20.2 in the PM), area under the curve (689 in the AM vs.259 in the PM); and, sensitivity of the ACTH dose-response curve (first significant increase in ACTH with 1 IU of vasopressin in the AM but not significant even after 3 IU in the PM). In addition, when the AM vasopressin testing followed a previous evening stimulation (PM/AM protocol), there was a blunted ACTH response compared with the AM/PM protocol.Corticotropin-releasing factor (CRF) is probably the major ACTH secretagogue, but since vasopressin acts synergistically with CRF to produce an augmented release of ACTH, we suggest that the ACTH response to administered vasopressin depends upon the ambient endogenous level of CRF. We interpret our data and published data that CRF produces a lesser release of ACTH in the AM as follows: in the morning endogenous CRF is high and administered CRF produces little further release of ACTH, but administered vasopressin acting synergistically with high endogenous CRF causes a greater release of ACTH; conversely, in the evening endogenous CRF is low and administered CRF causes a greater release of ACHI, but vasopressin (a weak secretagogue by itself) gives a low ACTH response. We conclude that vasopressin stimulation of ACTH secretion can be used as an in vivo bioassay of endogenous CRF, and that there is a diurnal rhythm of CRF in hypophyseal portal blood.

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Section: Discussionmentioning

confidence: 83%

Vasopressin stimulation of adrenocorticotropin hormone (ACTH) in humans. In vivo bioassay of corticotropin-releasing factor (CRF) which provides evidence for CRF mediation of the diurnal rhythm of ACTH.

Salata¹,

Jarrett²,

Verbalis³

et al. 1988

J. Clin. Invest.

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“…This affinity shift, however, appears to be limited to the brain since peripheral AVP receptors (kid ney, liver, anterior pituitary) do not show affinity changes in the HO-BB rat compared to the HE-BB rat [27,39], The results on Bmax are comparable to those of Koch and Lutz-Bucher [39] who showed that in the anterior pituitary, the number of recep tors for AVP in the HO-BB rat are also increased, and that AVP treatment (via both acute intravenous injection and osmotic minipumps) can down-regulate AVP receptors to a level similar to those in HE-BB rats.…”

Section: Discussionmentioning

confidence: 90%

Regulation of Vasopressin Receptors and Phosphoinositide Hydrolysis in the Septum of Heterozygous and Homozygous Brattleboro Rats

et al. 1989

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Accurel polypropylene mini-devices, loaded with arginine vasopressin (AVP) and implanted in the lateral cerebral ventricle were used to centrally treat heterozygous (HE) and homozygous (HO) Brattleboro (BB) rats. After 1 week of treatment, the concentration of AVP receptors in the HO-BB rat septum decreased from 19.4 ± 2.6 to 12.4 ± 1.1 fmol/mg protein, but remained unchanged in the HE-BB rat (10.7 ± 0.8 and 7.0 ± 1.1 fmol/mg protein). In the HO-BB rat the [Η]-AVP equilibrium dissociation constant (K_D) of the septal AVP receptor decreased following AVP treatment (from 4.17 ± 0.7 to 1.97 ± 0.3 nM) compared to that of control animals. This decrease in receptor number following AVP treatment was accompanied by a decrease in the postreceptor response to AVP as measured by the AVP-stimulation of [³H]-inositol-1-phosphate (IP₁) accumulation (22.0 ± 6.1%) when compared to untreated animals (54.3 ± 8.3%). This apparent AVP-induced down-regulation was not due to occupancy of the binding sites by AVP since preincubation of the tissue at 37 °C for 60 min (which was able to cause near-complete dissociation of the hormone-receptor complex) did not result in an increased number of binding sites upon reexposure to [³H]-AVP. This study thus provides evidence for the homologous down-regulation and desensitization in terms of [³H]-IP₁ accumulation (phosphoinositide hydrolysis) of AVP receptors in the septum of the BB rat.

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“…A few small areas of POMC-positive cells did not seem to have CRH receptors in adjacent slides. Although this could be due to intrinsic variabilities in the two different methods used (i.e., autoradiography vs. in situ hybridization), or to the fact that the adjacent slides are 10 pm apart, it is also possible that some of the POMC cells lack CRH receptors and express receptors for other hypothalamic secretagogues, such as arginine vasopressin, a known stimulator of ACTH secretion [32,33], GR expression is widespread in the anterior pituitary, but their mRNA seems to be most highly concentrated in POMC cells. It is known from animal studies that other pituitary cells, such as lactotropes and somatotropes, are regulated by glucocorticoids, and that prolactin and growth hormone genes contain sequences that can bind the GR [34][35][36].…”

Section: Discussionmentioning

confidence: 99%

Localization and Quantification of Pro-Opiomelanocortin mRNA and Glucocorticoid Receptor mRNA in Pituitaries of Suicide Victims

et al. 1992

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Suicidal behavior has been associated with hypothalamic-pituitary-adrenal overactivity in humans, as measured by increased corticosteroid secretion. To investigate whether this overactivity is reflected at the pituitary level, we have studied the localization of pro-opiomelanocortin (POMC) mRNA, and glucocorticoid receptor (GR) mRNA, in human anterior pituitaries, and quantified these messages relative to controls. Pituitaries from 7 suicide victims and 11 cardiac deaths were sectioned into 10-µm slides, stained with thionin and processed for in situ hybridization using a riboprobe complementary to human POMC mRNA. To correct for possible postmortem cell loss, hybridization with P1B15, a cDNA complementary to rat cyclophillin mRNA, was used in adjacent sections. POMC mRNA containing cells were found to be localized in clusters and were highly associated with corticotropin-releasing hormone (CRH) receptors. In contrast, GR mRNA containing cells were distributed through the pituitary, although areas of increased density were associated with POMC mRNA cells. Quantification with a computerized image analysis system revealed a 25% increase in POMC message in suicide victims. Analysis of the corticotrophic cell clumps showed that the suicide victims had higher POMC mRNA density per cell (p = 0.04) and larger corticotrophic cell size (p = 0.04) than the cardiac death victims. No differences in GR mRNA were detected between the two groups, although GR and POMC mRNA levels were highly and significantly correlated (r = 0.8, p < 0.001). There were no differences in P1B15 message between the two groups. We conclude that in situ hybridization is a useful tool to study gene regulation in human neuroendocrine tissue and that suicide victims show evidence of chronic hypothalamic-pituitary-adrenal axis activation.

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Specific Receptors for Vasopressin in the Pituitary Gland: Evidence for Down-Regulation and Desensitization to Adrenocorticotropin-Releasing Factors

Cited by 85 publications

References 15 publications

Vasopressin stimulation of adrenocorticotropin hormone (ACTH) in humans. In vivo bioassay of corticotropin-releasing factor (CRF) which provides evidence for CRF mediation of the diurnal rhythm of ACTH.

Vasopressin stimulation of adrenocorticotropin hormone (ACTH) in humans. In vivo bioassay of corticotropin-releasing factor (CRF) which provides evidence for CRF mediation of the diurnal rhythm of ACTH.

Regulation of Vasopressin Receptors and Phosphoinositide Hydrolysis in the Septum of Heterozygous and Homozygous Brattleboro Rats

Localization and Quantification of Pro-Opiomelanocortin mRNA and Glucocorticoid Receptor mRNA in Pituitaries of Suicide Victims

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