Summary
The effect of the opiate antagonist naloxone on serum prolactin after treatment with serotonin, arginine vasotocin (AVT) or melatonin was studied in prepubertal and adult unanesthetized rats. Prolactin was quantified in blood samples withdrawn through an intrajugular silastic cannula from undisturbed ovariectomized adult rats.
After taking a basal sample, animals were injected through the cannula with naloxone (0.8 mg/kg) and 5 min later with serotonin creatinine sulphate (6.4 mg/kg), AVT (20μg/kg), melatonin (4 mg/kg) or saline; new samples were taken 15 and 30 min thereafter. Injection of serotonin was followed by a 10-fold increase of prolactin levels 15 min later; this increase was drastically reduced, although not abolished, by pretreatment with naloxone. In animals injected with saline, AVT or melatonin, no significant changes in serum prolactin were observed.
In a second group of experiments, 30 day-old female rats injected with serotonin creatinine sulphate (10 mg/kg, i.p.) exhibited a 6-fold increase in serum prolactin 15 min after injection; this increment was reduced but not abolished by pretreatment with naloxone (5 mg/kg, i.p.).
It is postulated that the prolactin releasing effect of serotonin is mediated, at least in part, by an opioid receptor.
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Arakelian, M. C., Libertun, C.: H1 and H2 histamine receptors participation in the brain control of prolactin secretion in lactating rats. Endocrinology100, 890–895 (1977).
Becú, D., Libertun, C.: Comparative maturation of the regulation of prolactin and thyrotropin by serotonin and thyrotropin-releasing hormone in male and female rats. Endocrinology110, 1879–1884 (1982).
Blank, M. S., Paneari, A. E., Friesen, H. G.: Effect of naloxone on luteinizing hormone and prolactin in serum of rats. J. Endocrinology85, 307–315 (1980).
Blask, D. E., Vaughan, M. K.: Naloxone inhibits arginine vasotocin (AVT)-induced prolactin release in urethane anesthetized male ratsin vivo. Neuroscience Letters18, 181–184 (1980).
Bruni, J. F., Van Vugt, D., Marshall, S., Meites, J.: Effect of naloxone, morphine and metionin enkephalin on serum prolactin, luteinizing hormone, follicle stimulating hormone, thyroid stimulating hormone and growth hormone. Life Sciences21, 461–466 (1977).
Cardinali, D. P.: Melatonin. A mammalian pineal hormone. Endocrine Rev.2, 327–346 (1981).
Goldstein, A.: Opioid peptides (endorphins) in pituitary and brain. Science193, 1081–1086 (1976).
Krulich, L., Mc Cann, S. M., Mayfield, M. A.: On the mode of the prolactin release inhibiting action of the serotonin receptor blockers metergoline, methysergide and cyproheptadine. Endocrinology108, 1115–1124 (1981).
Libertun, C., Arakelian, M. C., Larrea, G. A., Goriño, L. R., Becú, D.: Neurotrasmisores, neurohormonas y prolactina. Acta Physiol. Latinoamer.30, 275–289 (1980).
Matsushita, N., Kato, Y., Katakami, H., Shimatsu, A., Imura, H.: Inhibition by naloxone of prolactin release induced by L 5 hydroxytryptophan in rats. Proc. Soc. Exptl. Biol. Med.168, 282–285 (1981).
Miki, N., Sonntag, L., Forman, L. J., Meites, J.: Suppression by naloxone of rise in plasma growth hormone and prolactin induced by suckling. Proc. Soc. Exptl. Biol. Med.168, 330–333 (1981).
Sapun, D. I., Farah, J. M., Muller, G. P.: Evidence that a serotoninergic mechanism stimulates the secretion of pituitary endorphin like immunoreactivity in the rat. Endocrinology109, 421–426 (1981).
Shin, S. H.: Blockage of ether induced surge of prolactin by naloxone in male rats. J. Endocrinology79, 397–398 (1978).
Simontov, R., Snyder, S. H.: Opiate receptor binding in the pituitary gland. Brain Res.124, 178–184 (1977).
Spaminato, S., Locatelli, V., Cocchi, D., Vicentini, L., Bajusz, S., Ferri, S., Muller, E. E.: Involvement of brain serotonin in the prolactin releasing effect of opioid peptides. Endocrinology105, 163–169 (1979).
Pilotte, N. S., Porter, J. C.: Dopamine in hypophyseal portal plasma and prolactin in systemic plasma of rats treated with 5-hydroxytryptamine. Endocrinology108, 2137–2141 (1981)
Van Vugt, D. A., Bruni, J. F., Meites, J.: Naloxone inhibition of stress induced increase in prolactin secretion. Life Sci.22, 85–90 (1978).
Vaughan, M. R.: Arginine vasotocin and vertebrate reproduction. In: The Pineal Gland. Vol. II. Reproductive Effects (Reiter, R. J., ed.), pp. 125–163. Boca Raton: CRC Press. 1981.
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This work was supported by grants from the Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina.
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Somoza, G.M., Larrea, G.A., Becú, D. et al. Inhibition by naloxone of the serotonin-induced prolactin release in free-moving rats. J. Neural Transmission 56, 97–102 (1983). https://doi.org/10.1007/BF01243378
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DOI: https://doi.org/10.1007/BF01243378