623
The Determination of Immunoreactive B-Endorphin Concentration in the Human Fetal and Neonatal Thymus M. Jevremovic1 , M. Terzic1 , G. Kartaljevic1 V.Popovic2, B. Rosic1 and S. Filipovic3 University Clinical Center, Clinic of Gynecology and Obstetrics and Institute for Endocrinology, Diabetes and Metabolic Diseases, Belgrade Institute for Oncology, Laboratory of Biochemistry, Nis, Yugoslavia
branation process (Ibata and Kawakami 1985), put in 5 ml of homogenization buffer. p-EP determination was based on the evaluation of concentrations in both membranes and cytosol and only in cytosol of Thymus is, according to the contemporary opinion, a the thymus and placenta cell substrate by using radioimmunoassay part of hypothalamic-pituitary-gonadal-thymic axis and participates techniques (RIA-Nichols Institute). So results were expressed in pg of in the regulation and modulation of the endocrine reproductive functions in humans {Hall, McGillis and Spangelo 1985). We studied the en- B-EP in gram of wet tissue weight, mean ± SD.B-EPconcentrations in peripheral blood were determined using RIA Nichols kits. docrine properties of the human fetal thymus during the gestational periods and found that it contained significant b-endorphin activity. The obtained data were analyzed by Student's t- and x2-test on computer IBM PC AT 3 86. B-endorphin (B-EP) is a neurohormone (neuropeptide) cleaved from precursor pro-opiomelanocortin (POMC) and under the control of CRH (Corticotropin Releasing Hormone). B-EP Results is generated in the CNS, hypothalamus and anterior pituitary (AM and Vatson 1984), but it is detected in the ovarian, testicular and Immunoreactive B-EP in human thymus was found placental tissue as well (Sharp anAPeckary 1981). to increase in thymic cellular substrates with the progression of gestation. This finding was markedly expressed in FTH and NTH samples In the thymus gland, a variety of neuropeptides and consisting of both cytosol and membranes, reaching very high levels neuroactive substances have been localized immunocytochemically, (x = 3816 ± 732 pg/g). The concentrations of B-EP in FTH and NTH including Oxytocin, Vasopressin, Neurophysins, Substance P (SP), cytosol only were also high, but did not show characteristic variations Vasoactive Intestinal Peptide (VIP), Somatostatin, Aminobutyric acid in levels during gestational period and delivery (Figure 1). and Calcitonin. Furthermore, lymphocytes have shown to synthesize most, if not all, the neuroendocrine peptide hormones (Khansari, We stress the interesting fact thatB-EPwas high both Murgo and Faith 1990). It has been confirmed that B-EP can be proin thymic neuroendocrine zone and placental compartment duced in the thymic cells, especially in the neuroendocrine subcapsu(x = 4224 ±870 pg/g). Immunoreactive B-EP levels in peripheral lar zone, but also in lymphoid cellular elements (Gilman and Schwarts blood of nonpregnant women were x = 44 ± 9 pg/ml. 1982). We therefore investigated the production and the concentrations ofB-EPin the human fetal and neonatal thymus during the gestation (third trimester) and in the immediate neontal period. Material and Methods We determined the concentrations ofB-EPin human fetal (FTH) autopsy immediately after spontaneous preterm labor in the ninth (n = 4) and ninth and a half (n = 4) month of gestation as well as at term delivery (n = 4). This study was performed in collaboration with the Department of Clinical Pathology of Gynecological Clinic, Institute for Endocrinology, Diabetes and Metabolic Diseases, University Clinical Center in Belgrade and Laboratory of Biochemistry of Oncological Institute in Nis. Peripheral blood samples of nongravid healthy persons (n = 5) were taken as controls. This opioid neurohormone was also investigated in placental compartments of normal pregnancies in the same month of gestation as thymus glands (n = 14). After they were obtained, thymic and placental tissue specimens were placed directly into liquid nitrogen and transported to the laboratory. One gram of tissue was cut and, after the microdismem-
Horm.metab.Res.23(1991)623-624 © Georg Thieme Verlag Stuttgart • New York
Discussion In pregnancy, and particularly during labour which represents an extremely stressful situation, maternal and fetal production of bloodB-EPis increased (Pilkington 1983), which our study confirmed. Thymus is incorporated in the hypothalamic-pituitarygonadal-thymic axis and production (secretion) of opioid peptides in the neuroendocrine subcapsular zone of thymus is likely to be increased (Hall, McGillis and Spangelo 1985). There is a putative bidirectional network carrying information between the immune and reproductive systems. While hypophyseal and gonadal hormones feedback information to the thymic cells exists, providing a modulatory system, regulating thymic cell maturation and thymic peptide production, the thymus and its peptides secretion can exert a modulation of gonadotropin secretion via a direct action at the hypothalamic LHRH level (Marchetti, Morale, Guarcello, Cutuli, Gallo and Scapagnini 1990). Neurohormone B-EP appears to have a significant physiological role as a regulator of pain perception, by increasing the threshold of this perception and as an endocrine factor in human reproduction. B-EP stimulates secretion of Prolactin (PRL), Growth hormone (GH) and Vasopressin (AVP), and inhibits production of Oxytocin (OT), Dopamine, Folliculostimulating (FSH) and Luteiniz-
Received: 7 Febr. 1991
Accepted: 18 Aug. 1991 after revision
Downloaded by: York University libraries. Copyrighted material.
Introduction
Horm. metab. Res. 23 (1991)
M. Jevremovic, M. Terzic, G. Kartaljevic, V. Popovic, B. Rosic and S. Filipovic Fig. 1 Concentrations of B-endorphin in human fetal and neonatal thymus and placenta.
ing (LH) hormone, resulting in depression of copulative effects, that is, it exerts anti-reproductive influence both in female and male reproductive tract (Genazzani and Petraglia 1988). It is worth noting that neuroendocrine compartment of the thymus was found to produce several neurohormones, including B-EP and oxytocin (Jevremovic, Barbijeri, Arambasic, Kartaljevic, Kovacevic and Pazin 1990; Jevremovic, Arambasic, Kartaljevic, Kovacevic, Pazin and Terzic 1991) which show antagonistic effects. This interaction has already drawn the attention of investigators in the field of neuroendocrinology. It has been found that B-EP protects the reproductive system from both the excessive secretion and effects of pituitary trophic hormones. The mechanism of opioid peptide action is via opioid receptors and can be antagonized by competitive binding antagonist Naloxone. Naloxone and its possible relationship to fetal endorphin levels and fetal distress have been studied by Goodlin (1981). The results obtained in this study could suggest that the identified increased B-EP production in both membranes and cell substrate cytosol from fetal and neonatal thymus are most probably caused by intrapartal stress. As an alternative hypothesis we propose that B-EP of the thymic origin represents an anti-reproductive factor, throughout intrauterine fetal and early neonatal life. Endocrinology of thymus requires further research in order to obtain a definitive exact insight in human reproduction.
References Akil, H., S. J. Vatson: Ann. Rev.Neuroscience 7:223-226 (1984) Genazzani, A. R., F. Petraglia: J. Clin. Endocrinol. Metabol. 66: 279— 283(1988)
Gilman, S. C, J. M. Schwarts: Proc. Nat. Acad. Sci. USA 79: 42264230(1982) Goodlin, R. C: Am. J. Obstet. Gynecol. 139:19-25 (1981) Hall, N. R., J. P. McGillis, B. L. Spangelo: J. Immunol. 135: 806-809 (1985) Ibata, Y., F. Kawakami: Brain Res. 341:223-228 (1985) Jevremovic, M., M. Barbijeri, M. Arambasic, G. Kartaljevic, D. Kovacevic, S. Pazw: Thymus 15:181-185(1990) Jevremovic, M., M. Arambasic, G. Kartaljevic, D. Kovacevic, S. Pazin, M. Terzic: J. Perinatol. (1991, in press) Khansari, D. N., A. J. Murgo, R. E. Faith: Immunol. Today 11 (5): 257-263(1990) Marchetti, B., M. C. Morale, V. Guarcello, N. Cutuli, F. Gallo, U. Scapagnini: In: E. Y. Adashi, S. Mancuso. Serono Symposia Publications from Raven Press, Raven Press, New York 73: 251—257 (1990) Pilkington.J. W.:Am. J. Obstet.Gynecol. 145:111-117(1983) Sharp, B., E. Peckary: J. Clin. Endocrinol. Metabol. 52: 586-591 (1981)
Requests for reprints should be addressed to: Prof. Dr. Milan Jevremovic, M. D., Ph. D. Head of Maternity Ward Department University Clinical Center Gyn/Ob Clinic Visegradska 26 11000 Belgrade (Yugoslavia)
Downloaded by: York University libraries. Copyrighted material.
624
The Determination of Immunoreactive B-Endorphin Concentration in the Human Fetal and Neonatal Thymus M. Jevremovic1 , M. Terzic1 , G. Kartaljevic1 V.Popovic2, B. Rosic1 and S. Filipovic3 University Clinical Center, Clinic of Gynecology and Obstetrics and Institute for Endocrinology, Diabetes and Metabolic Diseases, Belgrade Institute for Oncology, Laboratory of Biochemistry, Nis, Yugoslavia
branation process (Ibata and Kawakami 1985), put in 5 ml of homogenization buffer. p-EP determination was based on the evaluation of concentrations in both membranes and cytosol and only in cytosol of Thymus is, according to the contemporary opinion, a the thymus and placenta cell substrate by using radioimmunoassay part of hypothalamic-pituitary-gonadal-thymic axis and participates techniques (RIA-Nichols Institute). So results were expressed in pg of in the regulation and modulation of the endocrine reproductive functions in humans {Hall, McGillis and Spangelo 1985). We studied the en- B-EP in gram of wet tissue weight, mean ± SD.B-EPconcentrations in peripheral blood were determined using RIA Nichols kits. docrine properties of the human fetal thymus during the gestational periods and found that it contained significant b-endorphin activity. The obtained data were analyzed by Student's t- and x2-test on computer IBM PC AT 3 86. B-endorphin (B-EP) is a neurohormone (neuropeptide) cleaved from precursor pro-opiomelanocortin (POMC) and under the control of CRH (Corticotropin Releasing Hormone). B-EP Results is generated in the CNS, hypothalamus and anterior pituitary (AM and Vatson 1984), but it is detected in the ovarian, testicular and Immunoreactive B-EP in human thymus was found placental tissue as well (Sharp anAPeckary 1981). to increase in thymic cellular substrates with the progression of gestation. This finding was markedly expressed in FTH and NTH samples In the thymus gland, a variety of neuropeptides and consisting of both cytosol and membranes, reaching very high levels neuroactive substances have been localized immunocytochemically, (x = 3816 ± 732 pg/g). The concentrations of B-EP in FTH and NTH including Oxytocin, Vasopressin, Neurophysins, Substance P (SP), cytosol only were also high, but did not show characteristic variations Vasoactive Intestinal Peptide (VIP), Somatostatin, Aminobutyric acid in levels during gestational period and delivery (Figure 1). and Calcitonin. Furthermore, lymphocytes have shown to synthesize most, if not all, the neuroendocrine peptide hormones (Khansari, We stress the interesting fact thatB-EPwas high both Murgo and Faith 1990). It has been confirmed that B-EP can be proin thymic neuroendocrine zone and placental compartment duced in the thymic cells, especially in the neuroendocrine subcapsu(x = 4224 ±870 pg/g). Immunoreactive B-EP levels in peripheral lar zone, but also in lymphoid cellular elements (Gilman and Schwarts blood of nonpregnant women were x = 44 ± 9 pg/ml. 1982). We therefore investigated the production and the concentrations ofB-EPin the human fetal and neonatal thymus during the gestation (third trimester) and in the immediate neontal period. Material and Methods We determined the concentrations ofB-EPin human fetal (FTH) autopsy immediately after spontaneous preterm labor in the ninth (n = 4) and ninth and a half (n = 4) month of gestation as well as at term delivery (n = 4). This study was performed in collaboration with the Department of Clinical Pathology of Gynecological Clinic, Institute for Endocrinology, Diabetes and Metabolic Diseases, University Clinical Center in Belgrade and Laboratory of Biochemistry of Oncological Institute in Nis. Peripheral blood samples of nongravid healthy persons (n = 5) were taken as controls. This opioid neurohormone was also investigated in placental compartments of normal pregnancies in the same month of gestation as thymus glands (n = 14). After they were obtained, thymic and placental tissue specimens were placed directly into liquid nitrogen and transported to the laboratory. One gram of tissue was cut and, after the microdismem-
Horm.metab.Res.23(1991)623-624 © Georg Thieme Verlag Stuttgart • New York
Discussion In pregnancy, and particularly during labour which represents an extremely stressful situation, maternal and fetal production of bloodB-EPis increased (Pilkington 1983), which our study confirmed. Thymus is incorporated in the hypothalamic-pituitarygonadal-thymic axis and production (secretion) of opioid peptides in the neuroendocrine subcapsular zone of thymus is likely to be increased (Hall, McGillis and Spangelo 1985). There is a putative bidirectional network carrying information between the immune and reproductive systems. While hypophyseal and gonadal hormones feedback information to the thymic cells exists, providing a modulatory system, regulating thymic cell maturation and thymic peptide production, the thymus and its peptides secretion can exert a modulation of gonadotropin secretion via a direct action at the hypothalamic LHRH level (Marchetti, Morale, Guarcello, Cutuli, Gallo and Scapagnini 1990). Neurohormone B-EP appears to have a significant physiological role as a regulator of pain perception, by increasing the threshold of this perception and as an endocrine factor in human reproduction. B-EP stimulates secretion of Prolactin (PRL), Growth hormone (GH) and Vasopressin (AVP), and inhibits production of Oxytocin (OT), Dopamine, Folliculostimulating (FSH) and Luteiniz-
Received: 7 Febr. 1991
Accepted: 18 Aug. 1991 after revision
Downloaded by: York University libraries. Copyrighted material.
Introduction
Horm. metab. Res. 23 (1991)
M. Jevremovic, M. Terzic, G. Kartaljevic, V. Popovic, B. Rosic and S. Filipovic Fig. 1 Concentrations of B-endorphin in human fetal and neonatal thymus and placenta.
ing (LH) hormone, resulting in depression of copulative effects, that is, it exerts anti-reproductive influence both in female and male reproductive tract (Genazzani and Petraglia 1988). It is worth noting that neuroendocrine compartment of the thymus was found to produce several neurohormones, including B-EP and oxytocin (Jevremovic, Barbijeri, Arambasic, Kartaljevic, Kovacevic and Pazin 1990; Jevremovic, Arambasic, Kartaljevic, Kovacevic, Pazin and Terzic 1991) which show antagonistic effects. This interaction has already drawn the attention of investigators in the field of neuroendocrinology. It has been found that B-EP protects the reproductive system from both the excessive secretion and effects of pituitary trophic hormones. The mechanism of opioid peptide action is via opioid receptors and can be antagonized by competitive binding antagonist Naloxone. Naloxone and its possible relationship to fetal endorphin levels and fetal distress have been studied by Goodlin (1981). The results obtained in this study could suggest that the identified increased B-EP production in both membranes and cell substrate cytosol from fetal and neonatal thymus are most probably caused by intrapartal stress. As an alternative hypothesis we propose that B-EP of the thymic origin represents an anti-reproductive factor, throughout intrauterine fetal and early neonatal life. Endocrinology of thymus requires further research in order to obtain a definitive exact insight in human reproduction.
References Akil, H., S. J. Vatson: Ann. Rev.Neuroscience 7:223-226 (1984) Genazzani, A. R., F. Petraglia: J. Clin. Endocrinol. Metabol. 66: 279— 283(1988)
Gilman, S. C, J. M. Schwarts: Proc. Nat. Acad. Sci. USA 79: 42264230(1982) Goodlin, R. C: Am. J. Obstet. Gynecol. 139:19-25 (1981) Hall, N. R., J. P. McGillis, B. L. Spangelo: J. Immunol. 135: 806-809 (1985) Ibata, Y., F. Kawakami: Brain Res. 341:223-228 (1985) Jevremovic, M., M. Barbijeri, M. Arambasic, G. Kartaljevic, D. Kovacevic, S. Pazw: Thymus 15:181-185(1990) Jevremovic, M., M. Arambasic, G. Kartaljevic, D. Kovacevic, S. Pazin, M. Terzic: J. Perinatol. (1991, in press) Khansari, D. N., A. J. Murgo, R. E. Faith: Immunol. Today 11 (5): 257-263(1990) Marchetti, B., M. C. Morale, V. Guarcello, N. Cutuli, F. Gallo, U. Scapagnini: In: E. Y. Adashi, S. Mancuso. Serono Symposia Publications from Raven Press, Raven Press, New York 73: 251—257 (1990) Pilkington.J. W.:Am. J. Obstet.Gynecol. 145:111-117(1983) Sharp, B., E. Peckary: J. Clin. Endocrinol. Metabol. 52: 586-591 (1981)
Requests for reprints should be addressed to: Prof. Dr. Milan Jevremovic, M. D., Ph. D. Head of Maternity Ward Department University Clinical Center Gyn/Ob Clinic Visegradska 26 11000 Belgrade (Yugoslavia)
Downloaded by: York University libraries. Copyrighted material.
624
