Stimulation by Leumorphin of Prolactin Secretion from the Pituitary in Rats*
| Autor: | Hiroo Imura, Katsuyoshi Tojo, Yasuhiro Kabayama, Akira Shimatsu, Norio Matsushita, Yuzuru Kato, Noboru Yanaihara, Hikaru Ohta, Tatsuhide Inoue |
|---|---|
| Rok vydání: | 1985 |
| Předmět: |
Male
endocrine system Pituitary gland medicine.medical_specialty Swine Thyrotropin-releasing hormone Stimulation (+)-Naloxone Dynorphins chemistry.chemical_compound Endocrinology Anterior pituitary Pituitary Gland Anterior Internal medicine medicine Animals Endorphins Protein Precursors Thyrotropin-Releasing Hormone Injections Intraventricular Naloxone beta-Endorphin Enkephalins Prolactin Rats medicine.anatomical_structure chemistry hormones hormone substitutes and hormone antagonists |
| Zdroj: | Endocrinology. 117:1169-1174 |
| ISSN: | 1945-7170 0013-7227 |
| Popis: | The effect of leumorphin (LM), one of big leu-enkephalins derived from preproenkephalin B, on PRL secretion was studied in the rat in vivo and in vitro. Intracerebroventricular injection of synthetic porcine LM (0.06-6 nmol/rat) caused a dose-related increase in plasma PRL levels in urethane-anesthetized male rats and in conscious freely moving rats. Intravenous injection of LM (3 nmol/100 g BW) also raised plasma PRL levels in these animals. The plasma PRL response to intracerebroventricular LM (0.6 nmol/rat) was blunted by naloxone (125 micrograms/100 g BW, iv). The stimulating effect of LM on PRL release was the most potent among the peptides derived from preproenkephalin B. In in vitro studies, PRL release from superfused anterior pituitary cells was stimulated in a dose-related manner by LM (10(-9)-10(-6) M), and the effect was blunted by naloxone (10(-5) M). These results suggest that LM has a potent stimulating effect on PRL secretion from the pituitary in the rat by acting, at least in part, directly at the pituitary through an opiate receptor. |
| Databáze: | OpenAIRE |
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