, Volume 3, Issue 4, pp 273–275 | Cite as

Estrogen augments hypothalamicβ-endorphin secretion and activates an inhibitoryβ-endorphin short-loop feedback system

  • Sally A. Frautschy
  • Dipak K. Sarkar


The role of estrogen in the regulation of hypothalamicβ-endorphin hormone secretion is studied by determiningβ-endorphin concentration in pituitary portal plasma of ovariectomized rats in the presence or absence of this steroid and/or the opioid antagonist naloxone. Twenty-six hours following s.c. injection of 10 /µg estradiol benzoate (estrogen) or oil, rats anesthetized with Saffan (alphaxolone/alphadolone) underwent pituitary stalk exposure and hypophysectomy, after which pituitary portal blood was continuously collected and stored in 15 min aliquots from 1100–1400 h. At 1100 h, animals were given an initial bolus iv injection of naloxone or saline (naloxone, 2 mg/ kg, or saline, 0.1 ml) and then infused (iv) continuously with naloxone (2 mg/kg/h) or saline (0.8 ml/h) until 1400 h. Plasma samples were extracted and assayed by radioimmunoassay forβ-endorphin. Treatment with estrogen increased the meanβ-endorphin levels twofold as compared to oil-treated controls. Naloxone potentiated estrogen action ofβ-endorphin secretion, but did not affect basalβ-endorphin secretion. These results suggest that estrogen enhancedβ-endorphin secretion from the hypothalamus. Furthermore, the hypersecretion ofβ-endorphin induced by naloxone with, but not without, estrogen supports the existence of an estrogen-activated short-loop negative feedback mechanism regulatingβ-endorphin secretion.


Hypothalamicβ-endorphin secretion estrogen pituitary portal blood aphadolone/alphaxolone anesthesia ovariectomized rats short-loop feedback 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Akabori, A. & Barraclough, C.A. (1986).Brain Res.,362, 55–62.PubMedCrossRefGoogle Scholar
  2. Allen, L.G., Hahn, E., Caton, D. & Kalra, S.P. (1988).Endocrinology,122, 1004–1013.PubMedGoogle Scholar
  3. Almeida, O.F.X., Nikolarakis, K.E. & Herz, A. (1986).Nida Research Monograph,75, 401–402.PubMedGoogle Scholar
  4. Barraclough, C.A. & Sawyer, C.H. (1955).Endocrinology,57, 329–337.PubMedGoogle Scholar
  5. Bhanot, R. & Wilkinson, M. (1984).J. Endocr.,102, 133–141.PubMedCrossRefGoogle Scholar
  6. Bicknell, R.J. (1985).J. Endocr.,107, 437–446.PubMedCrossRefGoogle Scholar
  7. Carrer, J.F. & Aoki, A. (1982).Brain Res.,240, 221–233.PubMedCrossRefGoogle Scholar
  8. Ferin, M., Van Vugt, D. & Wardlaw, S. (1984).Recent Prog. Horm. Res.,40, 441–485.PubMedGoogle Scholar
  9. Fink, G. (1979).Ann. Rev. Physiol.,41, 571–585.CrossRefGoogle Scholar
  10. Frautschy, S.A. & Sarkar, D.K. (1988). Proc. 70th Ann. Meet. Endocrine Society, Abstr. 1193.Google Scholar
  11. Gabriel, S.M., Berglund, L.A. & Simpkins, J.W. (1986).Endocrinology,118, 558–561.PubMedGoogle Scholar
  12. Gabriel, S.M., Berglund, L.A. & Simpkins, J.W. (1987).Endocrinology,120, 1799–1804.PubMedGoogle Scholar
  13. Garcia-Segura, L.M., Olmos, G., Tranque, P. & Naftolin, F. (1987).J. Steroid Biochem.,27, 615–623.PubMedCrossRefGoogle Scholar
  14. Hammer, R.P., Jr. & Bridges, R.S. (1987).Brain Res.,420, 48–56.PubMedCrossRefGoogle Scholar
  15. Jirikowski, G.F., Merchenthaler, I.L., Rueger, G.E. & Stumpf, W.E. (1986).Neurosci. Lett.,65, 121–126.PubMedCrossRefGoogle Scholar
  16. Kalra, S.P. & Kalra, P.S. (1983).Endocrine Rev.,4, 311–351.Google Scholar
  17. Knuth, U.A., Sikand, G.S., Casanueva, F.F., Havlicek, V. & Friesen, H.G. (1983).Life Sci.,33, 1443–1450.PubMedCrossRefGoogle Scholar
  18. Koves, K., Marton, J., Molnar, J. & Halasz, B. (1981).Neuroendocrinology,32, 82–86.PubMedCrossRefGoogle Scholar
  19. Leranth, C., Sakamoto, H., MacLusky, N.J., Shanabrough, M. & Naftolin, F. (1985).Brain Res.,331, 376–381.PubMedCrossRefGoogle Scholar
  20. LaBella, F.S. (1985).Prog. Clin. Biol. Res.,192, 323–328.PubMedGoogle Scholar
  21. Lustig, R.H., Pfaff, D.W. & Fishman, F. (1988).J. Endocr.,116, 55–69.PubMedCrossRefGoogle Scholar
  22. Maggi, A. & Perez, J. (1984).Eur. J. Pharmacol.,103, 165–168.PubMedCrossRefGoogle Scholar
  23. Masotto, C. & Negro-Vilar, A. (1987).Endocrinology,121, 2251–2255.PubMedGoogle Scholar
  24. Matsumoto, A., Arai, Y. & Osanai, M. (1985).Neurosci. Res.,2, 412–418.PubMedCrossRefGoogle Scholar
  25. Minami, S. Xie, Q.W., Prasad, B.M., Advis, J.P. & Sarkar, D.K. (1992).Proc. Soc. Neurosci.,18, 111.Google Scholar
  26. Mocchetti, I. & Costa, E. (1987).Neuropharmacology,26, 855–862.PubMedCrossRefGoogle Scholar
  27. Morrell, J.I., McGinty, J.F. & Pfaff, D.W. (1985).Neuroendocrinology,41, 417–426.PubMedCrossRefGoogle Scholar
  28. Nikolarakis, K.E., Pfeiffer, D.G., Almeida, O.F.X. & Herz, A. (1986).Neuroendocrinology,44, 314–319.PubMedCrossRefGoogle Scholar
  29. Packman, P.M. & Rothchild, J.A. (1976).Endocrinology,99, 7–10.PubMedGoogle Scholar
  30. Pang, C.N., Zimmermann, C.H. & Sawyer, C.H. (1955).Endocrinology,101, 1726–1732.Google Scholar
  31. Petraglia, F., Locatelli, V., Penalra, A., Cocchi, D., Genazzani, A.R. & Muler, E.E. (1984).J. Endocr.,101, 33–39.PubMedCrossRefGoogle Scholar
  32. Petraglia, F., Locatelli, V., Facchinetti, F., Bergamaschi, M., Genazzani, A.R. & Cocchi, D. (1986).J. Endocr.,108, 89–94.PubMedCrossRefGoogle Scholar
  33. Petraglia, F., Sutton, S., Vale, W. & Plotsky, P. (1987).Endocrinology,120, 1083–1088.PubMedGoogle Scholar
  34. Piva, F., Limonta, P., Maggi, R. & Martini, L. (1984).The Opioid Modulation of Endocrine Function. Delitalia, G., Motta, M. & Scrio, M. (eds.). Raven Press: New York. pp. 155–164.Google Scholar
  35. Piva, F., Maggi, P., Limonta, M., Motta, M. & Martini, L. (1985).Endocrinology,117, 766–772.PubMedGoogle Scholar
  36. Rasmussen, D.D., Kennedy, B.P., Ziegler, M.G. & Nett, T.M. (1988).Endocrinology,123, 2916–2921.PubMedCrossRefGoogle Scholar
  37. Roberts, J.L., Wilcox, J.N. & Blum, M. (1986).Neuroendocrine Molecular Biology, Fink, A., Harmer, A.J., McKerns, K.W. (eds), Plenum Press: NY, pp. 261–275.Google Scholar
  38. Sar, M. & Stumph, W.E. (1981).Nature,289, 500–502.PubMedCrossRefGoogle Scholar
  39. Sarkar, D.K. (1988).Neuroendocrinology,45, 510–513.CrossRefGoogle Scholar
  40. Sarkar, D.K. & Yen, S.S.C. (1985).Endocrinology,116, 2075–2079.PubMedGoogle Scholar
  41. Wardlaw, S.L., Wang, P.J. & Frantz, A.G. (1985).Life Sci.,3, 1941–1947.CrossRefGoogle Scholar

Copyright information

© Humana Press Inc. 1995

Authors and Affiliations

  • Sally A. Frautschy
    • 1
  • Dipak K. Sarkar
    • 1
  1. 1.Department of Veterinary and Comparative Anatomy, Pharmacology and PhysiologyWashington State UniversityPullmanUSA

Personalised recommendations