Cellular Localization of a Prolactin-Like Antigen in the Rat Brain

Toubeau, Gérard; Desclin, Jean; Parmentier, Marc; Pasteels, Jean Lambert

doi:10.1677/joe.0.0830261

Cited by 81 publications

(37 citation statements)

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“…This agrees with other data showing the influences of PRL on the dopaminergic neuronal system in the hypothalamus [30] and with the pres ence of immunoreactive PRL in this brain area [31][32][33][34][35][36][37]. More over, the presence of PRL receptors in the substantia nigra should not be too surprising since evidence has been presented that PRL increases the activity of the nigroneostriatal dopami nergic neurons [4], and when bilaterally injected into the substantia nigra elicits grooming behavior in the rat [38], Values are means ± SD; n = number of experiments (in parentheses the number o f tissues pooled for each experiment).…”

Section: Discussionsupporting

confidence: 93%

Distribution and Characterization of Prolactin Binding Sites in the Male and Female Rat Brain: Effects of Hypophysectomy and Ovariectomy

1991

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The binding of ¹²⁵I-labeled rat prolactin (¹²⁵I-rat PRL) to membranes from different regions of the rat brain was studied. Among these regions the hypothalamus showed the highest specific binding. Clearly detectable specific binding was also observed in substantia nigra, whereas it was very scanty in other brain regions. No significant sex differences in PRL binding to various brain regions were observed, except for hypothalamus where a higher binding was observed in female rats. The binding of ¹²⁵I-rat PRL to hypothalamus from female rats was inhibited in a dose-dependent manner by both unlabeled rat and ovine PRL but not by several other polypeptide hormones. Scatchard analysis of the binding revealed the presence of the binding sites with low capacity and high affinity for rat ligand. Ovariectomy markedly decreased PRL binding in the hypothalamus; an even more pronounced decrease was found after hypophysectomy of female animals. A treatment with estradiol restored the PRL binding in the ovariectomized rats to above normal levels. These results of in vitro biochemical analysis together with the experimental modulation of hormonal status provide strong preliminary evidence for the presence of PRL binding sites in rat brain.

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Section: Discussionsupporting

confidence: 93%

Distribution and Characterization of Prolactin Binding Sites in the Male and Female Rat Brain: Effects of Hypophysectomy and Ovariectomy

1991

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“…Thus, a-MSH repre sents another example of a peptide with a hormonal role in the pituitary and a possible neurotransmitter function in the central nervous system [3,15,21,23,27]. Such dual func tions have already been suggested for other peptides, such as prolactin, ACTH, vasopressin and opioid peptides [4,20,26,31], Our results reveal diurnal differences in the amount of hypothalamic a-MSH released by high potassium. Only at 10.00 h when we observed a measurable spontaneous a-MSH release, could enhanced release be elicited by high potassium.…”

Section: Discussionsupporting

confidence: 72%

Diurnal Variation in the Release of Alpha-MSH from Rat Hypothalamus and Pituitary

Monnet¹,

Reubi²,

Eberlé³

et al. 1981

Neuroendocrinology

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Release of α-MSH from rat hypothalamic slices was characterized with respect to ionic requirements and possible diurnal variations using a sensitive radioimmunoassay. Addition of 47 mM KCl to the superfusion medium resulted in a twofold increase in α-MSH release compared to spontaneous release. Removal of calcium from the superfusion medium abolished the potassium-evoked release of α-MSH. This supports the concept that α-MSH functions as a neurotransmitter or neuromodulator in the hypothalamus. Both spontaneous and potassium-induced α-MSH release were related to diurnal variation. Marked release from the slices was observed at 10.10 h, corresponding to a peak in the α-MSH concentration in the hypothalamus [18] and to a low level of α-MSH in the blood. Contrarily, no significant release from the hypothalamus was obtained at 17.00 h when hypothalamic α-MSH content was low, but blood levels exhibited a peak. These findings suggest that there are differences in the regulation of the α-MSH from the pituitary and that in the hypothalamus.

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“…Production of brain PRL has been supported by immunocytochemical, RIA, and bioassay data from normal and hypophysectomized animals (18)(19)(20). Using RT-PCR, Emanuele and colleagues (21) demonstrated the presence of PRL mRNA in whole hypothalamus and in several brain extrahypothalamic regions, indicating the expression of PRL in the brain.…”

Section: Discussionmentioning

confidence: 98%

The prolactin gene is expressed in the hypothalamic-neurohypophyseal system and the protein is processed into a 14-kDa fragment with activity like 16-kDa prolactin.

Clapp

Torner²,

Gutiérrez‐Ospina³

et al. 1994

Proc. Natl. Acad. Sci. U.S.A.

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The 23-kDa form of prolactin (PRL) has been proposed to function as both a mature hormone and a prohormone precursor for different uniquely bioactive forms of the molecule. We have shown that the 16-kDa N-terminal fragent of PRL (16K PRL) inhibits angiogenesis via a specific receptor. In addition, 16K PRL stimulates natriuresis and diuresis In the rat, and kidney membranes contain high-affinity specific binding sites for this PRL fragent. 16K PRL can be derived from an enzymatically cleaved form of PRL (cleaved PRL). With the use of a specific 16K PRL antiserum, we have loalid a 14-kDa immunoreactive protein in the paraventricular and supraoptic nuclei of the hypothalamus and in the neurohypophysis. Reverse transcription-polymerase chain reaction of RNA from isolated paraventricular nuclei showed the expression of the full-length PRL mRNA. The neurohypophysis was found to contain the enzymes that produce cleaved PRL, small amounts of PRL, and cleaved PRL. Medium conditioned by neurohypophyseal cultures, enriched with the 14-kDa immunoreactive protein, has antiaogenic effects that are blocked by the 16K PRL antiserum. These results are consistent with the expression of PRL in the hypothamicneurohypophyseal system, and the preferential processing of the protein into a 14-kDa gent with biological and immunological properties of 16K PRL.

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Cellular Localization of a Prolactin-Like Antigen in the Rat Brain

Cited by 81 publications

References 0 publications

Distribution and Characterization of Prolactin Binding Sites in the Male and Female Rat Brain: Effects of Hypophysectomy and Ovariectomy

Distribution and Characterization of Prolactin Binding Sites in the Male and Female Rat Brain: Effects of Hypophysectomy and Ovariectomy

Diurnal Variation in the Release of Alpha-MSH from Rat Hypothalamus and Pituitary

The prolactin gene is expressed in the hypothalamic-neurohypophyseal system and the protein is processed into a 14-kDa fragment with activity like 16-kDa prolactin.

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