Summary
Pimozide, a specifie blocker of dopaminergic receptors, was injected for 4 or 9 days in freshwater (FW) eels or eels acclimated to sea water (SW) for 10 or 30 days. The daily dose was 100 or 200 μg/100g. Melanophore index values increase in FW and in 1 month-SW injected eels. All the treated fish react by a total or subtotal degranulation of the lead-hematoxylin positive cells in the pars intermedia. These cells were previously identified as α-MSH-secreting cells. The MSH cell nuclear area is significantly increased, nucleoli are larger and the endoplasmic reticulum more developed. The intensity of the response is similar in FW and SW eels, but it does not increase with the higher dose. The rapid release of pituitary α-MSH is also visualized by immunofluorescence and immunoenzymologic techniques. No effect on the second cell type of the pars intermedia (PAS-positive cell) is detected. The amount of neurosecretory material is often reduced in the neurohypophysis. These results suggest that the hypothalamic inhibitory control of MSH release and synthesis is mediated through dopaminergic fibers in the eel, but other factors cannot be ignored in this regulation.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Båge, G., Ekengren, B., Fernholm, B., Fridberg, G.: The pituitary gland of the roach Leuciscus rutilus. III. Pars intermedia and its innervation. Acta zool. (Stockh.) 56, 43–60 (1975)
Baker, B.I.: Sécrétion de l'hormone mélanostimulante par l'hypophyse de poisson in vitro. Biol. Méd. 56, 351–358 (1967)
Baker, B.I.: The cellular source of melanocyte stimulating hormone in anguilla pituitary. Gen comp. Endocr. 19, 515–521 (1972)
Corbin, A., Upton, G.V., Mabry, G.C., Hollingsworth, D.R.: Diencephalic involvement in generalized lipodystrophy: rationale and treatment with the neuroleptic agent, pimozide. Acta endocr. (Kbh.) 77, 209–220 (1974)
Follénius, E.: Intégration de la dopamine dans les terminaisons aminergiques de la métaadénohypophyse de l'Épinoche (Gasterosteus aculeatus) C.R. Acad. Sci. (Paris), Sér. D, 273, 1039–1040 (1971)
Fremberg, M., Meurling, P.: Catecholamine fluorescence in the pituitary of the eel Anguilla anguilla, with special reference to its variation during background adaptation. Cell Tiss. Res. 157, 53–72 (1975)
Fremberg, M., Olivereau, M.: Melanophore responses and intermediate-lobe activity in the eel Anguilla anguilla after injection of 6-OH-dopamine. Acta zool. (Stockh.) 54, 231–239 (1973)
Goos, H.J.T., Terlou, M.: Hypothalamic control of MSH secretion in lower vertebrates. Frontiers of Hormone Research, Vol. 4, pp. 51–62. Basel: Karger 1977
Janssen, P.AJ., Niemegeers, C.J.E., Schellekens, K.H.L., Dresse, A., Lenaerts, F.M., Pinchard, A., Schaper, W.K.A., Van Nueten, J.M., Verbruggen, F.J.: Pimozide, a chemically novel, highly potent and orally long-acting neuroleptic drug. I. The comparative pharmacology of pimozide, haloperidol and chlorpromazine. Arzneimittel-Forsch. 18, 261–279 (1968)
Kah, O., Chambolle, P., Olivereau, M.: Innervation aminergique hypothalamo-hypophysaire chez Gambusia sp. (Téléostéen Poecilidé) étudiée par deux techniques de fluorescence. C.R. Acad. Sci. (Paris) sér D 286, 705–708 (1978)
Kastin, A.J., Schally, A.V., Viosca, S.: Inhibition of MSH in frogs by direct application of L-prolyl-1-leucyl-glycinamide to the pituitary. Proc. Soc. exp. Biol. (N.Y.) 137, 1437–1439 (1971)
Knowles, F., Vollrath, L.: Neurosecretory innervation of the pituitary of the eels Anguilla and Conger. I. The structure and ultrastructure of the neuro-intermediate lobe under normal and experimental conditions. Phil. Trans. B 250, 311–327 (1966)
Morgan, C.M., Hadley, M.E.: Ergot alkaloid inhibition of melanophore stimulating hormone secretion. Neuroendocrinol. 21, 10–19 (1976)
Olivereau, M.: Complexe neuro-intermédiaire et osmorégulation. Comparaison chez l'Anguille Européenne et chez l'Anguille Japonaise d'élevage au cours du transfert en eau de mer. Z. Zellforsch. 99, 389–410 (1969a)
Olivereau, M.: Activité de la pars intermedia de l'hypophyse autotransplantée chez l'Anguille. Z. Zellforsch. 98, 74–87 (1969b)
Olivereau, M.: Coloration de l'hypophyse avec l'hématoxyline au plomb (H.Pb): données nouvelles chez les Téléostéens et comparaison avec les résultats obtenus chez d'autres Vertébrés. Acta zool. (Stockh.) 51, 229–249 (1970)
Olivereau, M.: Elaboration d'intermédine par les cellules colorées avec l'hématoxyline au plomb dans la pars intermedia de l'Anguille: preuves nouvelles et contrôle hypothalamique. C.R. Acad. Sci. (Paris) 272, sér. D 102–105 (1971)
Olivereau, M.: Action de la réserpine chez l'Anguille. II. Effet sur la pigmentation et le lobe intermédiaire. Comparaison avec l'effet de l'adaptation sur un fond noir. Z. Anat. Entwickl.-Gesch. 137, 30–46 (1972a)
Olivereau, M.: Hypothalamic control of MSH release in eels with in situ or ectopic pituitary gland. Excerp. Med. Internation. Congr. Ser. No. 256, 136 (1972b)
Olivereau, M.: Hypothalamic control of MSH secretion in lower vertebrates. Folia anat. Iugosl. 4, 15–21 (1975)
Olivereau, M.: Régulation des sécrétions de prolactine (PRL) et de MSH chez l'Anguille. J. de Physiol. 72, 51A (1976)
Olivereau, M.: Effect of pimozide on the cytology of the eel pituitary. I. Prolactin-secreting cells. Cell Tiss. Res. 189, 219–230 (1978)
Olivereau, M., Ball, J.N.: Histological study of functional ectopic pituitary transplants in a teleost fish (Poecilia formosa). Proc. roy. Soc. B 164, 106–129 (1966)
Olivereau, M., Bugnon, C., Fellmann, D.: Localisation cytoimmunologique d' α-MSH et d'ACTH dans les cellules hypophysaires colorables avec l'hématoxyline au plomb (H.Pb) chez l'Anguille. C.R. Acad. Sci. (Paris), Sér. D 283, 1321–1323 (1976)
Penny, R.J., Thody, A.J., Tilders, F.J.H., Smelik, P.G.: Effect of dopamine receptor blockers on pituitary and plasma melanocyte-stimulating hormone levels in the rat. J. Endocr. 72, 27P (1977)
Platt, J.E., Norris, D.O.: The effect of ergocornine on melanophores of Ambystoma tigrinum: evidence for suppression of pituitary MSH release. J. exp. Zool. 189, 7–12 (1974)
Rychter, J., Stepien, H.: Effects of pimozide and bromocriptine on the proliferation of rat pituitary pars intermedia cells. J. Endocr. 75, 443–444 (1977)
Sage, M.: Control of prolactin release and its role in colour change in the teleost Gillichthys mirabilis. J. exp. Zool. 173, 121–128 (1970)
Smith, A.F.: The effect of apomorphine and ergocriptine on the release of MSH by the pars intermedia of Rana pipiens. Neuroendocrinology 19, 363–376 (1975)
Thornton, V.F., Howe, C.: The effect of change of background colour on the ultrastructure of the pars intermedia of the pituitary of the eel (Anguilla anguilla). Cell Tiss. Res. 151, 103–115 (1974)
Trygstad, O., Foss, I.: Congenital generalized lipodystrophy and experimental lipoatrophic diabetes in rabbits treated successfully with fenfluramine. Acta endocr. (Kbh.) 85, 436–448 (1977)
Author information
Authors and Affiliations
Additional information
The author is grateful to Dr. P.A.J. Janssen for donating the pimozide used in this experiment and to Jacqueline Olivereau, from the C.N.R.S., for her excellent technical assistance. This work was supported by the Centre National de la Recherche Scientifique and a grant from the Délégation Générale à la Recherche Scientifique et Technique (n∘ A 650 1588)
Rights and permissions
About this article
Cite this article
Olivereau, M. Effect of pimozide on the cytology of the eel pituitary. Cell Tissue Res. 189, 231–239 (1978). https://doi.org/10.1007/BF00209272
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00209272