Radioautographic identification of lactogen binding sites in rat median eminence using 125I-human growth hormone
Creators
- 1. McGill Univ., Montreal, Quebec (Canada). Faculty of Medicine
- 2. George Washington Univ., Washington, DC (USA). Dept. of Anatomy
Description
The binding characteristics of human growth hormone were exploited to identify radioautographically lactogen binding sites in the rat median eminence following systemic injection 125I-human growth hormone bound preferentially to the lateral palisade zone, a region of median eminence rich in dopamine and LHRH. Coinjection of 125I-human growth hormone with an excess of unlabeled human growth hormone or ovine prolactin, but not bovine growth hormone, competitively blocked 125I-human growth hormone binding to the external median eminence. These observations provide direct evidence of recognition sites for lactogenic hormones in a discrete region of the median eminence associated with hypothalamic regulation of hypophyseal prolactin and luteinizing hormone secretion. Median eminence lactogen binding sites may mediate presumed direct effects of lactogenic hormones on the reproductive functions of the hypophysiotropic hypothalamus. (orig.)
Abstract (German)
Die Bindungscharakteristiken des Wachstumshormons wurden zur autoradiographischen Bestimmung von Lactogenbindungsorten im Medianhoecker der Ratte verwendet, und zwar nach einer Systeminjektion von 125J-HGH, das vorzugsweise an den lateralen Palisadenbereich, einen Dopamin- und LHRH-reichen Bereich des Medianhoeckers, gebunden war. Eine Koinjektion von 125J-HGH mit einem Ueberschuss an unmarkiertem HGH oder Schafprolactin, jedoch nicht Rinderwachstumshormon, bewirkte eine kompetitive Blockierung der Bindung von HGH an den aeusseren Medianhoecker. Diese Ergebnisse sprechen fuer die Existenz von Orten zur Erkennung von Lactogenhormonen in einem diskreten Bereich des Medianhoeckers, der an der hypothalamischen Steuerung der Sekretion von Hypophysenprolactin und interstitialzellenstimulierenendem Hormon beteiligt sind. Die Lactogenbindungsorte im Medianhoecker uebermitteln moeglicherweise die bisher als direkt angenommene Wirkung der Lactogenhormone auf die Reproduktionsfunktion des hypophysiotropen Hypothalamus. (orig.)Additional details
Additional titles
- Subtitle (English)
- Evidence for a prolactin 'Short-loop' feedback site
Publishing Information
- Journal Title
- Exp. Brain Res.
- Journal Volume
- 38
- Journal Issue
- 4
- Series
- Exp. Brain Res.
- Journal Page Range
- 455-461
- ISSN
- 0014-4819
INIS
- Country of Publication
- Germany
- Country of Input or Organization
- Germany
- INIS RN
- 12581540
- Subject category
- S62: RADIOLOGY AND NUCLEAR MEDICINE;
- Descriptors DEI
- AUTORADIOGRAPHY; IODINE 125; LABELLING; LTH; MAN; RECEPTORS; STH
- Descriptors DEC
- ANIMALS; BETA DECAY RADIOISOTOPES; DAYS LIVING RADIOISOTOPES; ELECTRON CAPTURE RADIOISOTOPES; GONADOTROPINS; HORMONES; INTERMEDIATE MASS NUCLEI; IODINE ISOTOPES; ISOTOPES; MAMMALS; NUCLEI; ODD-EVEN NUCLEI; PEPTIDE HORMONES; PITUITARY HORMONES; PRIMATES; RADIOISOTOPES; VERTEBRATES
Optional Information
- Notes
- A preliminary report of these findings was presented at the Annual Meeting of the Canadian Society for Clinical Investigation, Feb 5, 1979, Montreal, and appeared in Clinical Research 26, 874A (1979).