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Expression of prolactin receptors and regulation of cell proliferation by prolactin, corticotropin-releasing factor, and corticosterone in a neuroblastoma cell line.

The aetiology of neuroblastoma remains obscure, although a number of neuropeptides have been implicated in its pathogenesis. Using the mouse neuroblastoma cell line Neuro2a as a model, we have investigated the mitogenic actions of prolactin (PRL) and two hypothalamo–pituitary–adrenal stress axis hormones, corticotropin-releasing factor (CRF) and corticosterone. Using established polyclonal PRL receptor antisera with immunofluorescence cytochemistry, we show that the Neuro2a cells possess immunoreactive forms of both the long and short forms of the receptor. PRL and CRF were effective as mitogens in Neuro2a cell cultures, where a 10[sup –7] M concentration of PRL or CRF elicited a two-fold increase in the numbers of cells after 72 h (p < 0.0001). Corticosterone, however, attenuated their proliferation. These data suggest that prolactin may act to increase the proliferation and regulation of neuroblastomas and that the effects of PRL may be modified by hypothalamo–pituitary–adrenal hormones.Key words: cell proliferation, mitogens, neuroblasts, stress, cancer.Bien que certains neuropeptides interviendraient dans la pathogenèse, l'étiologie des neuroblastomes demeure obscure. Nous avons étudié les effets mitogènes de la prolactine (PRL) et de deux hormones de stress de l'axe hypothalamo–hypophyso–surrénalien, la corticolibérine (CRF) et la corticostérone, en utilisant comme modèle la lignée cellulaire de neuroblastome de souris, Neuro2a. Nous montrons que les cellules Neuro2a ont la forme longue et la forme courte du récepteur de la PRL (PRL-R) à l'aide de la cytochimie par immunofluorescence en utilisant des antisérums polyclonaux anti-PRL-R. La PRL et la CRF sont de bons mitogènes des cellules Neuro2a en culture, puisque le nombre de cellules double après 72 h d'incubation en présence de la PRL ou de la CRF 10[sup –7] M (p < 0,0001). Par contre, la corticostérone ralentit la prolifération des cellules. Ces résultats suggèrent que la PRL agirait en augmentant la prolifération et la régulation des neuroblastomes et que ses effets seraient modifiés par des hormones de l'axe hypothalamo–hypophyso–surrénalien.Mots clés : prolifération cellulaire, mitogènes, neuroblastes, stress, cancer.[Traduit par la Rédaction] [ABSTRACT FROM AUTHOR]

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