Biochemical study of prolactin binding sites in <i>Xenopus laevis</i> brain and choroid plexus

Muccioli, Giampiero; Guardabassi, A.; Pattono, Paola Maria

doi:10.1002/jez.1402530310

Cited by 15 publications

(10 citation statements)

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“…Dissociation constants were very similar across brain areas and not substantially different from the 0.2-0.3 nM K<i values obtained in pre vious studies on membranes from dove forebrain and midbrain [ 12], Kj values of approximately this magnitude have also been reported in hypothalamic membranes from rabbit, rat, and horse [19,20,36] and from mem brane fractions prepared from amphibian brain tissue [ 17,18], As would be expected from the nonuniform dis tribution of PRL binding sites and the dilution effect that would occur when binding capacity estimates are calcu lated from large, heterogenous brain areas, Bmax estimates for each of the PRL-sensitive brain regions in the present study were higher than the 3-5 fmol/mg protein values previously reported for pooled dove forebrain and mid brain membranes [12], Fig. 6.…”

Section: Discussionsupporting

confidence: 69%

“…Pro lactin receptors that could conceivably mediate these changes have been detected and partially characterized in crude membrane fractions prepared from ring dove brain homogenates [12], Subsequent mapping of these receptors by in vitro autoradiography revealed a nonuniform distribution in midbrain and forebrain with highest specific binding activity in the choroid plexus, the ventromedial, suprachiasmatic, and periventricular hypothalamic nuclei, the tuberal hypothalamic region, and the preoptic area [ 13], Although species differences are apparent, a similar pattern of l25I-ovine (o) PRL binding site distribution has been reported in rabbit brain [14] and in the CNS of four songbird species [15,16] using the same in vitro autoradiographic technique. The precise distribution of CNS specific binding sites for PRL in other vertebrate species remains unknown, although PRL binding sites have been detected in brain tissue homogenates or membrane fractions prepared from several amphibian [17,18], avian [19], and mam malian [19,20] representatives.…”

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confidence: 99%

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Prolactin Receptors in Dove Brain: Autoradiographic Analysis of Binding Characteristics in Discrete Brain Regions and Accessibility to Blood-Borne Prolactin

Buntin¹,

Ruzycki²,

Witebsky³

1993

Neuroendocrinology

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Film autoradiography and densitometry were employed to obtain a detailed map of prolactin (PRL) receptor distribution in ring dove brain and to characterize the affinity, capacity, specificity, and in vivo saturability of ¹²⁵I-ovine PRL binding in individual brain regions. Significant specific binding was detected in choroid plexus and in a variety of forebrain and midbrain sites, with highest levels observed in the preoptic area, tuberoinfundibular region, lateral hypothalamic area, and the suprachiasmatic, paraventricular, and ventromedial hypothalamic nuclei. A comparison of PRL receptors in the choroid plexus, preoptic area, ventromedial nucleus, suprachiasmatic nucleus, and tuberal hypothalamus revealed significant regional differences in binding capacity, but no differences in binding affinity (K_d = 0.4-0.9 nM; B_max = 6-14 fmol/mg protein). Unlabelled ovine PRL proved to be an effective competitor of labelled ovine PRL at concentrations of 43 pM, 0.43 nM, and 4.3 nM in the choroid plexus and in 5 diencephalic areas. In contrast, no significant competition was observed in any of these brain areas in tests with unlabelled turkey GH, ovine GH, or ovine LH at similar concentrations. Unlabelled ovine PRL (37 nmol) significantly reduced the uptake of ¹²⁵I-ovine PRL (37 pmol) in the preoptic area, tuberal hypothalamus, and bed nucleus of the pallial commissure at 2 h after intravenous injection. In addition, specific binding of ¹²⁵I-ovine PRL in vitro was reduced by over 67% in these brain areas and in several other brain regions following a 7 day period of systemic ovine PRL administration. These results indicate that PRL receptors in different regions of the dove brain exhibit similar binding characteristics. In addition, they suggest that at least some of these PRL-sensitive brain loci are accessible to blood-borne hormone.

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Section: Discussionsupporting

confidence: 69%

mentioning

confidence: 99%

Prolactin Receptors in Dove Brain: Autoradiographic Analysis of Binding Characteristics in Discrete Brain Regions and Accessibility to Blood-Borne Prolactin

Buntin¹,

Ruzycki²,

Witebsky³

1993

Neuroendocrinology

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“…In mammals, choroid plexus PRLR has been proposed to be involved in the transport of PRL from the blood into the cerebrospinal fluid (Walsh et al 1987). In Xenopus, high specific binding has been found in the choroid plexus of the brain by use of an in vitro PRL binding assay (Muccioli et al 1990). These results suggest that PRLR in the choroid plexus of the amphibian brain may also serve for transporting PRL from the blood into the cerebrospinal fluid.…”

Section: Discussionmentioning

confidence: 99%

“…In the rat, PRLR-like immunoreactivity has been observed in numerous nuclei of the telencephalon, such as those in the cerebral cortex, hippocampal formation, and amygdaloid nuclei (Roky et al 1996). In Xenopus, a relatively low level of specific PRL binding occurs in the telencephalon (Muccioli et al 1990). Therefore, PRLR expression levels may be low in the telencephalon of amphibian species.…”

Section: Discussionmentioning

confidence: 99%

Localization of prolactin receptor in the newt brain

et al. 2005

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In the male newt Cynops pyrrhogaster, prolactin (PRL) acts directly on the central nervous system and induces courtship behavior. As a step to elucidate the localization of neurons on which PRL acts, we developed a polyclonal antibody against an oligopeptide having a sequence completely identical with a part of the sequence of PRL receptors (PRLRs) of two species of newts, C. pyrrhogaster and C. ensicauda, and performed an immunohistochemical study with this antibody. PRLR-immunoreactive cells were observed in the medial amygdala, anterior preoptic area, magnocellular preoptic nucleus, suprachiasmatic nucleus, nucleus of the periventricular organ, ventral hypothalamic nucleus, and choroid plexus. We also performed in situ hybridization with a (35)S-labeled newt PRLR antisense RNA probe and detected signals in the preoptic area and choroid plexus. Colocalization of both PRLR-like immunoreactivity and arginine vasotocin-like or mesotocin-like immunoreactivity was demonstrated in the magnocellular preoptic nucleus. This is the first report of PRLR localization in the amphibian brain.

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“…In the newt T. cristatus, the courtship behavior center is presumed to be located in the preoptic area, as lesions to this area abolish sexual behavior (Malacarne and Giacoma, 1980). According to Muccioli et al (1990), PRL-binding sites in the brain of Xenopus are located in the hypothalamus and choroid plexus. These investigators assumed that PRL-binding at the level of the choroid plexus may play a role in transporting the hormone across the bloodcerebrospinal fluid barrier.…”

Section: Hormonal Control Of Courtship Behaviormentioning

confidence: 99%

Endocrine regulation of reproductive behavior in the newt Cynops pyrrhogaster

Toyoda

Kikuyama

2000

Zoological Science

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Hormonal control of the expression of courtship behavior and of secretion of the female-attracting pheromone sodefrin by the male red-bellied newt, Cynops pyrrhogaster, together with the hormonal influence on the responsiveness to the pheromone in the female, is reviewed.Expression of the initial stage of the courtship behavior, i.e., tail vibration by the male in front of the female, is dependent on prolactin (PRL) and androgen. During the courtship, sodefrin seems to be released from the cloaca through the ducts of the abdominal gland. Both content of immunoreactive sodefrin and preprosodefrin mRNA levels in the abdominal gland are elevated by a combination of PRL and androgen, indicating that the pheromone synthesis is stimulated by these two hormones. On the other hand, the discharge of sodefrin is accelerated by AVT, its action being mediated by V1 receptor. In female newts, responsiveness of the vomeronasal epithelium to the pheromone is elevated by a combination of PRL and estrogen. Thus, it can be concluded that PRL, AVT, and sex steroids are key hormones for the reproductive performance in the red-bellied newt. In this article, the significance of the structure of the pheromone molecule as a peptide is also discussed in terms of its species-specificity and its effectiveness in an aquatic environment.

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Biochemical study of prolactin binding sites in Xenopus laevis brain and choroid plexus

Cited by 15 publications

References 75 publications

Prolactin Receptors in Dove Brain: Autoradiographic Analysis of Binding Characteristics in Discrete Brain Regions and Accessibility to Blood-Borne Prolactin

Prolactin Receptors in Dove Brain: Autoradiographic Analysis of Binding Characteristics in Discrete Brain Regions and Accessibility to Blood-Borne Prolactin

Localization of prolactin receptor in the newt brain

Endocrine regulation of reproductive behavior in the newt Cynops pyrrhogaster

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