Prolactin Binding Sites in the Rat Brain

Walsh, Raymond J.; Posner, Barry I.; Kopriwa, Beatrix Markus; Brawer, James R.

doi:10.1126/science.684427

Cited by 141 publications

(52 citation statements)

References 10 publications

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“…The epithelial cells of the choroid plexus possess high affinity PRL receptors (6,7,26,27) that may represent sites of transport of PRL from blood to CSF. If a receptor-mediated process is involved, then efficiency of transport may be influenced by the endocrine state of the animal.…”

Section: Discussionmentioning

confidence: 99%

Immunoreactive Prolactin in the Cerebrospinal Fluid of Estrogen‐Treated and Lactating Rats as Determined by Push‐pull Perfusion of the Lateral Ventricles

Rubin¹,

Bridges²

1989

J Neuroendocrinology

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lmmunoreactive (ir) prolactin levels in the cerebrospinal fluid were measured in push-pull perfusion samples collected from the lateral cerebral ventricles in freely-moving ovariectomized rats prior to and after estrogen treatment, and in rats during pregnancy and lactation. Ir-prolactin levels in cerebrospinal fluid were elevated throughout the perfusion period in ovariectomized animals given estrogen and in Day 8 lactating females following the onset of nursing by their young. Cerebrospinal fluid perfusates collected from ovariectomized animals prior to estradiol treatment and from females on Days 18 and 22 of gestation contained levels of irprolactin that were below the limit of detectability of the prolactin radioimmunoassay. Data from previous studies in our laboratory suggest that pituitary prolactin is involved in the mediation of maternal responsiveness. Where and how prolactin exerts its actions in this regard remains to be determined. Results of the present study indicate that detectable levels of ir-prolactin are present in the cerebrospinal fluid of nulliparous females after exposure to an estradiol regimen known to shorten their latency to display maternal responsiveness and in lactating females actively exhibiting maternal behavior. Once in the cerebrospinal fluid, prolactin should have access to neural target sites behind the blood-brain barrier. The presence of ir-prolactin in the cerebrospinal fluid of females in the present study is consistent with a role for this protein hormone, acting at the level of the central nervous system, in the facilitation of maternal responsiveness as well as in the regulation of other neural and neuroendocrine processes.

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Section: Discussionmentioning

confidence: 99%

Immunoreactive Prolactin in the Cerebrospinal Fluid of Estrogen‐Treated and Lactating Rats as Determined by Push‐pull Perfusion of the Lateral Ventricles

Rubin¹,

Bridges²

1989

J Neuroendocrinology

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“…This view is strengthened by evidence for PRL binding sites in specific forebrain regions of the rabbit (17), pig (18), horse (19), toad (20) and ring dove (21,22). PRL binding has also been reported in the choroid plexus of rat (23), horse, calf (19), ring dove (24), sheep, pig and rabbit (18). Although their function has yet to be established, it has been proposed that PRL binding sites in the choroid plexus may be involved in the transport of PRL from blood to cerebrospinal fluid (25), thereby providing a possible route by which blood-borne PRL could gain access to target cells in periventricular brain areas.…”

mentioning

confidence: 96%

Changes in Feeding Activity, Plasma Luteinizing Hormone, and Testes Weight in Ring Doves Following Hypothalamic Injections of Prolactin

Foreman

Lea

Buntin

1990

J Neuroendocrinology

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Microinjections of ovine prolactin were administered unilaterally to the ventromedial hypothalamic nucleus and the preopticsuprachiasmatic region in adult male ring doves in an attempt to determine the site(s) at which intracranial injections of prolactin act to alter feeding behaviour and gonadotropin secretion in this species. Food intake and body weight were measured daily during a 6-day pretreatment period and the 5-day treatment period that immediately followed. During the treatment period, birds received twice daily injections (0.5 PI) of either 2.5 ng ovine prolactin or saline vehicle. An additional group of birds with cannulae in the ventromedial nucleus were given twice daily injections of 25 ng ovine prolactin. Although food consumption was unaffected by low dose prolactin treatment, birds given 25 ng prolactin injections into the ventromedial nucleus showed a significant augmentation in food intake. Injections of 25 ng prolactin into the preoptic area also increased feeding; however, the magnitude of this hyperphagic response, as expressed relative to pretreatment levels, was less than that observed following prolactin injection into the ventromedial nucleus. No differences were observed between prolactin-treated and vehicle-treated birds in either cannulation group when testes weights and plasma luteinizing hormone concentrations were compared at the end of the treatment period. However, the possibility that prolactin influenced changes in luteinizing hormone and testes weight relative to baseline values could not be assessed due to constraints imposed by the experimental paradigm used. These results suggest that prolactin-sensitive neurons in the ventromedial hypothalamic region and the preoptic area are potential sites of prolactin action in promoting hyperphagia in ring doves. However, the role of these sites in mediating prolactin-induced suppression of gonadotropin secretion in this species remains to be clarified.

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“…The purpose of the present report was to investigate the possibility that PRL acts at the level of the central nervous system to stimulate maternal behavior. A central site of PRL action is feasible in light of a series of findings that indicate that circulating PRL can gain access to the brain through active transport across the blood-cerebrospinal fluid (CSF) barrier (10), that PRL, presumably of pituitary origin, is found in increased amounts within the CSF at times when circulating levels of PRL are elevated (11)(12)(13), and that receptors for PRL have been localized within the central nervous system (14)(15)(16)(17)(18).…”

mentioning

confidence: 99%

Central prolactin infusions stimulate maternal behavior in steroid-treated, nulliparous female rats.

Bridges

Numan

Ronsheim

et al. 1990

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

304

202

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A series of experiments were conducted to determine whether and under what conditions central prolactin (PRL) administration would stimulate the onset of maternal behavior in female rats and to identify possible neural sites of PRL action. In each experiment ovariectomized, nulliparous rats whose endogenous PRL levels were suppressed with bromocriptine were tested for maternal behavior toward foster young. In experiments 1, 2, and 4, females were also exposed to pregnancy-like levels of progesterone (days 1-11) followed by estradiol (days 11-17). In experiment 1 infusions (days 11-13) of four doses of ovine PRL (400 ng, 2 ,ug, 10 ,ug, or 50 jug, but not 80 ng) into the lateral ventricle resulted in a rapid onset of maternal behavior (behavioral testing, days 12-17). The stimulatory action of these doses of PRL appears to be central, since subcutaneous injections of 50 jug of ovine PRL failed to affect maternal responsiveness (experiment 2). Experiment 3 indicated that the stimulatory effect of intracerebroventricularly administered PRL is steroid dependent. Infusions of either 10 ,ug of ovine PRL or 10 1ug of rat PRL failed to induce maternal behavior in nonsteroid-treated animals. In the final experiment (no. 4) bilateral infusions of 40 ng of ovine PRL into the medial preoptic area of steroid-treated rats resulted in a pronounced stimulation of maternal behavior. These findings demonstrate a central site of PRL action in the stimulation of maternal responsiveness and point to the medial preoptic area as a key neural site for PRL regulation of maternal behavior.The hormonal changes accompanying pregnancy and parturition play a critical role in preparing the female to respond maternally toward her newborn young (1-4). One hormone that recently was shown to have a key role in inducing maternal behavior is the pituitary hormone prolactin (PRL) (5, 6). PRL and other members of the PRL family-i.e., growth hormone and placental lactogens-are secreted in large amounts during pregnancy (7-9), making these molecules potential physiological regulators of maternal behavior. Eliminating or suppressing PRL secretion in steroid-treated, ovariectomized, nulliparous rats by either hypophysectomy or administration of bromocriptine, a dopamine agonist, blocks the rapid onset of maternal behavior (5, 6). These effects are prevented when PRL is given to hypophysectomized or bromocriptine-treated female rats.Although PRL stimulates the onset of maternal behavior, little is known about PRL's site of action. The purpose of the present report was to investigate the possibility that PRL acts at the level of the central nervous system to stimulate maternal behavior. A central site of PRL action is feasible in light of a series of findings that indicate that circulating PRL can gain access to the brain through active transport across the blood-cerebrospinal fluid (CSF) barrier (10), that PRL, presumably of pituitary origin, is found in increased amounts within the CSF at times when circulating levels of PRL are elevated (11-13), ...

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Prolactin Binding Sites in the Rat Brain

Abstract: The principles of the competitive-binding assay were used in conjunction with light microscopic radioautography to demonstrate specific prolactin binding sites localized on ependyma of the rat choroid plexus, a previously unknown prolactin target tissue.

Cited by 141 publications

References 10 publications

Immunoreactive Prolactin in the Cerebrospinal Fluid of Estrogen‐Treated and Lactating Rats as Determined by Push‐pull Perfusion of the Lateral Ventricles

Immunoreactive Prolactin in the Cerebrospinal Fluid of Estrogen‐Treated and Lactating Rats as Determined by Push‐pull Perfusion of the Lateral Ventricles

Changes in Feeding Activity, Plasma Luteinizing Hormone, and Testes Weight in Ring Doves Following Hypothalamic Injections of Prolactin

Central prolactin infusions stimulate maternal behavior in steroid-treated, nulliparous female rats.

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