[3H]Dihydroergocryptine binding in anterior pituitary and prolactin secretion: Further evidence of brain regulation of adenohypophyseal receptors
Secretion of PRL by the pituitary gland is under tonic inhibitory control by tuberoinfundibular dopaminergic neurons. The aim of the present work was to assess the influence of the hypothalamus on the binding of [3H]dihydroergocryptine, a dopamine agonist, in the adenohypophysis and its role in the...
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todo:paper_00137227_v107_n6_p1905_Libertun2023-10-03T14:11:05Z [3H]Dihydroergocryptine binding in anterior pituitary and prolactin secretion: Further evidence of brain regulation of adenohypophyseal receptors Libertun, C. Larrea, G.A. Vacas, M.I. Cardinali, D.P. dihydroergotoxine dopamine dopamine receptor prolactin tritium apomorphine dopamine haloperidol hormone receptor radioisotope adenohypophysis animal article blood castration drug effect female hypothalamus hypophysis system kinetics median eminence metabolism physiology rat adenohypophysis animal experiment brain injury central nervous system dihydroergocryptine h 3 drug binding endocrine system hypothalamus median eminence prolactin release Animal Castration Dihydroergotoxine Dopamine Female Hypothalamo-Hypophyseal System Kinetics Median Eminence Pituitary Gland, Anterior Prolactin Rats Receptors, Dopamine Support, Non-U.S. Gov't Tritium Secretion of PRL by the pituitary gland is under tonic inhibitory control by tuberoinfundibular dopaminergic neurons. The aim of the present work was to assess the influence of the hypothalamus on the binding of [3H]dihydroergocryptine, a dopamine agonist, in the adenohypophysis and its role in the hypoprolactinemic action of exogenous dopamine. Serum PRL levels were elevated in ovariectomized adult rats with electrolytic lesions of the median eminence compared to levels in sham-operated animals; [3H]dihydroergocryptine binding to anterior pituitary was elevated from a control value of 161.2 ± 7.7 to 229.0 ± 10.0 fmol/mg protein in rats studied 7-21 days after placement of the lesion (P < 0.05). Scatchard analysis of [3H]dihydroergocryptine binding in lesioned and sham-operated animals indicated an increase of 62% in the number of binding sites without a change in binding affinity. In a second group of rats, with or without median eminence destruction, the effects of different doses of ip dopamine on serum PRL were determined. The hypoprolactinemic effect of each dose of the amine was more evident in median eminencelesioned rats than in sham-operated controls. These results suggest that when hypothalamic influences on the anterior pituitary are removed, there is increased binding of dopamine by the gland and increased hypoprolactinemic effects of the exogenous amine. This indicates that receptors in the pituitary are under hypothalamic control, and this could be an important regulatory mechanism in neuroendocrine events. © 1980 by The Endocrine Society. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_00137227_v107_n6_p1905_Libertun |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
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Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
dihydroergotoxine dopamine dopamine receptor prolactin tritium apomorphine dopamine haloperidol hormone receptor radioisotope adenohypophysis animal article blood castration drug effect female hypothalamus hypophysis system kinetics median eminence metabolism physiology rat adenohypophysis animal experiment brain injury central nervous system dihydroergocryptine h 3 drug binding endocrine system hypothalamus median eminence prolactin release Animal Castration Dihydroergotoxine Dopamine Female Hypothalamo-Hypophyseal System Kinetics Median Eminence Pituitary Gland, Anterior Prolactin Rats Receptors, Dopamine Support, Non-U.S. Gov't Tritium |
| spellingShingle |
dihydroergotoxine dopamine dopamine receptor prolactin tritium apomorphine dopamine haloperidol hormone receptor radioisotope adenohypophysis animal article blood castration drug effect female hypothalamus hypophysis system kinetics median eminence metabolism physiology rat adenohypophysis animal experiment brain injury central nervous system dihydroergocryptine h 3 drug binding endocrine system hypothalamus median eminence prolactin release Animal Castration Dihydroergotoxine Dopamine Female Hypothalamo-Hypophyseal System Kinetics Median Eminence Pituitary Gland, Anterior Prolactin Rats Receptors, Dopamine Support, Non-U.S. Gov't Tritium Libertun, C. Larrea, G.A. Vacas, M.I. Cardinali, D.P. [3H]Dihydroergocryptine binding in anterior pituitary and prolactin secretion: Further evidence of brain regulation of adenohypophyseal receptors |
| topic_facet |
dihydroergotoxine dopamine dopamine receptor prolactin tritium apomorphine dopamine haloperidol hormone receptor radioisotope adenohypophysis animal article blood castration drug effect female hypothalamus hypophysis system kinetics median eminence metabolism physiology rat adenohypophysis animal experiment brain injury central nervous system dihydroergocryptine h 3 drug binding endocrine system hypothalamus median eminence prolactin release Animal Castration Dihydroergotoxine Dopamine Female Hypothalamo-Hypophyseal System Kinetics Median Eminence Pituitary Gland, Anterior Prolactin Rats Receptors, Dopamine Support, Non-U.S. Gov't Tritium |
| description |
Secretion of PRL by the pituitary gland is under tonic inhibitory control by tuberoinfundibular dopaminergic neurons. The aim of the present work was to assess the influence of the hypothalamus on the binding of [3H]dihydroergocryptine, a dopamine agonist, in the adenohypophysis and its role in the hypoprolactinemic action of exogenous dopamine. Serum PRL levels were elevated in ovariectomized adult rats with electrolytic lesions of the median eminence compared to levels in sham-operated animals; [3H]dihydroergocryptine binding to anterior pituitary was elevated from a control value of 161.2 ± 7.7 to 229.0 ± 10.0 fmol/mg protein in rats studied 7-21 days after placement of the lesion (P < 0.05). Scatchard analysis of [3H]dihydroergocryptine binding in lesioned and sham-operated animals indicated an increase of 62% in the number of binding sites without a change in binding affinity. In a second group of rats, with or without median eminence destruction, the effects of different doses of ip dopamine on serum PRL were determined. The hypoprolactinemic effect of each dose of the amine was more evident in median eminencelesioned rats than in sham-operated controls. These results suggest that when hypothalamic influences on the anterior pituitary are removed, there is increased binding of dopamine by the gland and increased hypoprolactinemic effects of the exogenous amine. This indicates that receptors in the pituitary are under hypothalamic control, and this could be an important regulatory mechanism in neuroendocrine events. © 1980 by The Endocrine Society. |
| format |
JOUR |
| author |
Libertun, C. Larrea, G.A. Vacas, M.I. Cardinali, D.P. |
| author_facet |
Libertun, C. Larrea, G.A. Vacas, M.I. Cardinali, D.P. |
| author_sort |
Libertun, C. |
| title |
[3H]Dihydroergocryptine binding in anterior pituitary and prolactin secretion: Further evidence of brain regulation of adenohypophyseal receptors |
| title_short |
[3H]Dihydroergocryptine binding in anterior pituitary and prolactin secretion: Further evidence of brain regulation of adenohypophyseal receptors |
| title_full |
[3H]Dihydroergocryptine binding in anterior pituitary and prolactin secretion: Further evidence of brain regulation of adenohypophyseal receptors |
| title_fullStr |
[3H]Dihydroergocryptine binding in anterior pituitary and prolactin secretion: Further evidence of brain regulation of adenohypophyseal receptors |
| title_full_unstemmed |
[3H]Dihydroergocryptine binding in anterior pituitary and prolactin secretion: Further evidence of brain regulation of adenohypophyseal receptors |
| title_sort |
[3h]dihydroergocryptine binding in anterior pituitary and prolactin secretion: further evidence of brain regulation of adenohypophyseal receptors |
| url |
http://hdl.handle.net/20.500.12110/paper_00137227_v107_n6_p1905_Libertun |
| work_keys_str_mv |
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| _version_ |
1807322387609288704 |