Release of beta-endorphin-immunoreactivity from rat pituitary and hypothalamus in vitro: effects of isoproterenol, dopamine, corticotropin-releasing factor and arginine8-vasopressin.
The release of beta-endorphin-immunoreactivity (beta E-IR) from rat pituitary anterior lobe (AL) quarters, neurointermediate lobes (NILs), and hypothalamic fragments was investigated in vitro. The beta-adrenoceptor agonist isoproterenol (ISO) and the hypothalamic neurohormone corticotropin-releasing factor (CRF) concentration-dependently stimulated the release of beta E-IR from superfused AL quarters and NILs, but not from incubated hypothalamic fragments. Dopamine (DA) inhibited the release of beta E-IR from NILs and hypothalamic tissue in a concentration-dependent manner, whereas it did not affect the release from AL quarters. Arginine8-vasopressin (AVP) stimulated the release of beta E-IR from AL quarters and hypothalamic fragments, but did not affect the release from NILs. The data indicate that the release of beta E-IR from cells in the pituitary lobes and in the hypothalamus is differentially regulated, but that common principles are involved. In particular, the results provide first direct evidence for an action of vasopressin as a stimulator of the release of POMC-derived peptides in the hypothalamus.
Sweep
C G
CG
Rudolf Magnus Institute, University of Utrecht, The Netherlands.
Wiegant
V M
VM
D000818:Animals; D001127:Arginine Vasopressin / Q000494:pharmacology*; D003346:Corticotropin-Releasing Hormone / Q000494:pharmacology*; D004298:Dopamine / Q000494:pharmacology*; D007031:Hypothalamus / Q000187:drug effects / Q000378:metabolism*; D007545:Isoproterenol / Q000494:pharmacology*; D008297:Male; D010477:Perfusion; D010903:Pituitary Gland, Anterior / Q000187:drug effects / Q000378:metabolism*; D011863:Radioimmunoassay; D051381:Rats; D011919:Rats, Inbred Strains; D001615:beta-Endorphin / Q000378:metabolism*
D001127:Arginine Vasopressin; D001615:beta-Endorphin; D003346:Corticotropin-Releasing Hormone; D007545:Isoproterenol; D004298:Dopamine