Selective effect of castration on the anterior pituitary VIP receptor of male rats

Wanke, Irene; Huang, Mengqi; Rorstad, O.P.

doi:10.1016/0196-9781(90)90146-v

“…They were then minced with scissors, homogenized observed. 16,17 Similar K d and B max values were found by polytron, and membranes were prepared by a series of centrifugations as previously described. 16 for the BDL and control rats, suggesting no perturba-The VIP receptor binding assay used a monoiodinated rations in the affinity or number of vascular VIP recepdioligand, [Tyr( 125 I) 10 ]VIP, prepared by radioiodination of tors in experimental cirrhosis (Table 3).…”

mentioning

confidence: 93%

Vasoactive intestinal peptide in cirrhotic rats: Hemodynamic effects and mesenteric arterial receptor characteristics

Lee

¹

1996

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Vasoactive intestinal peptide (VIP) blood levels in cirrhosis are elevated, but its hemodynamic and receptor characteristics remain unclarified. We aimed to quantify VIP receptor characteristics in mesenteric arteries, plasma VIP concentration by radioimmunoassay (RIA), and the hemodynamic effects of VIP infusion in bile duct-ligated (BDL) cirrhotic and sham-operated control rats. Mesenteric arterial membranes were prepared by ultracentrifugation, and receptor characteristics were studied using 125I-labeled VIP as a radioligand. For the hemodynamic study, there were four groups: cirrhotic and sham-operated rats were infused with either VIP (50 ng/kg/min for 15 minutes) or equivolumic isotonic saline. Regional blood flows were measured in conscious rats with radioactive microspheres. Receptor studies showed high- and low-affinity binding sites for VIP, which had similar equilibrium dissociation constants (binding affinities) and receptor densities for both the cirrhotic and control rats. Plasma VIP concentrations were significantly elevated in the cirrhotic rats. In both cirrhotic and sham-operated rats, VIP infusion produced plasma levels approximately twofold to threefold increased over the basal levels observed in cirrhotic rats. In cirrhotic rats, VIP infusion did not affect any hemodynamic parameter, whereas in the sham-operated rats VIP infusion significantly increased the mesenteric visceral blood flow. These results show that the hyporesponsiveness to VIP in cirrhotic rats is not attributable to receptor downregulation, implying postreceptor alterations. This suggests that VIP may not play a major role in the maintenance of splanchnic hyperemia in cirrhosis.

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“…Such heterogeneity with two binding sites has been previously demonstrated in numerous tissues examined, including arteries, brain, pituitary, prostate, and liver. 16,17,27 The physiological significance of the low-affinity site re- was not attributable to receptor downregulation, implicating changes in postreceptor factors.…”

mentioning

confidence: 94%

“…16,17 The re-DISCUSSION ceptor binding assay contained in a total volume of 200 mL, VIP is a 28-amino acid peptide with widespread tis- vasodilatory properties of this hormone, it has been ences in the cardiovascular responses to the VIP infusions. In agreement with previous studies showing that conjectured that VIP is the elusive endogenous humoral factor mediating the hyperdynamic circulation of VIP is a mesenteric vasodilator, 22-24 these moderately supraphysiological doses induced mesenteric visceral cirrhosis.…”

mentioning

confidence: 99%

“…They were then minced with scissors, homogenized observed. 16,17 Similar K d and B max values were found by polytron, and membranes were prepared by a series of centrifugations as previously described. 16 for the BDL and control rats, suggesting no perturbaThe VIP receptor binding assay used a monoiodinated ra-tions in the affinity or number of vascular VIP recep- (Table 3).…”

mentioning

confidence: 99%

See 1 more Smart Citation

Vasoactive intestinal peptide in cirrhotic rats: Hemodynamic effects and mesenteric arterial receptor characteristics

Lee

¹

,

Huang

²

,

Ma

³

et al. 1996

Hepatology

12

0

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Vasoactive intestinal peptide (VIP) blood levels in cirrhosis are elevated, but its hemodynamic and receptor characteristics remain unclarified. We aimed to quantify VIP receptor characteristics in mesenteric arteries, plasma VIP concentration by radioimmunoassay (RIA), and the hemodynamic effects of VIP infusion in bile duct-ligated (BDL) cirrhotic and sham-operated control rats. Mesenteric arterial membranes were prepared by ultracentrifugation, and receptor characteristics were studied using 125I-labeled VIP as a radioligand. For the hemodynamic study, there were four groups: cirrhotic and sham-operated rats were infused with either VIP (50 ng/kg/min for 15 minutes) or equivolumic isotonic saline. Regional blood flows were measured in conscious rats with radioactive microspheres. Receptor studies showed high- and low-affinity binding sites for VIP, which had similar equilibrium dissociation constants (binding affinities) and receptor densities for both the cirrhotic and control rats. Plasma VIP concentrations were significantly elevated in the cirrhotic rats. In both cirrhotic and sham-operated rats, VIP infusion produced plasma levels approximately twofold to threefold increased over the basal levels observed in cirrhotic rats. In cirrhotic rats, VIP infusion did not affect any hemodynamic parameter, whereas in the sham-operated rats VIP infusion significantly increased the mesenteric visceral blood flow. These results show that the hyporesponsiveness to VIP in cirrhotic rats is not attributable to receptor downregulation, implying postreceptor alterations. This suggests that VIP may not play a major role in the maintenance of splanchnic hyperemia in cirrhosis.

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“…There is evidence of morphological and functional relationships between neuroendocrine cells and prostate nerve fibres, resulting in a neuro-hormonal system that might modulate androgenic action in the prostate (Wanke et al, 1990;Abdul et al, 1995;Gkonos et al, 1995).…”

Section: Introductionmentioning

confidence: 99%

Evolution of Neuroendocrine Cell Population and Peptidergic Innervation, Assessed by Discriminant Analysis, During Postnatal Development of the Rat Prostate

Rodríguez¹,

Pozuelo²,

Alberca³

et al. 2011

Image Anal Stereol

1

0

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Serotonin immunoreactive neuroendocrine cells and peptidergic nerves (NPY and VIP) could have a role in prostate growth and function. In the present study, rats grouped by stages of postnatal development (prepubertal, pubertal, young and aged adults) were employed in order to ascertain whether age causes changes in the number of serotoninergic neuroendocrine cells and the length of NPY and VIP fibres. Discriminant analysis was performed in order to ascertain the classificatory power of stereologic variables (absolute and relative measurements of cell number and fibre length) on age groups. The following conclusions were drawn: a) discriminant analysis confirms the androgen-dependence of both neuroendocrine cells and NPY-VIP innervation during the postnatal development of the rat prostate; b) periglandular innervation has more relevance than interglandular innervation in classifying the rats in age groups; and c) peptidergic nerves from ventral, ampullar and periductal regions were more age-dependent than nerves from the dorso-lateral region.

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Selective effect of castration on the anterior pituitary VIP receptor of male rats

Cited by 5 publications

References 27 publications

Vasoactive intestinal peptide in cirrhotic rats: Hemodynamic effects and mesenteric arterial receptor characteristics

Vasoactive intestinal peptide in cirrhotic rats: Hemodynamic effects and mesenteric arterial receptor characteristics

Vasoactive intestinal peptide in cirrhotic rats: Hemodynamic effects and mesenteric arterial receptor characteristics

Evolution of Neuroendocrine Cell Population and Peptidergic Innervation, Assessed by Discriminant Analysis, During Postnatal Development of the Rat Prostate

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