Distribution of Met5-enkephalin-Arg6-Gly7-Leu8-immunoreactivity in the rat and mouse pituitary gland.
The distribution of the octapeptide Met5-enkephalin-Arg6-Gly7-Leu8 (MEAGL), a proenkephalin A-derived opioid peptide, in the rat and mouse pituitary gland was studied using the indirect immunofluorescence technique and immunoelectron microscopy. The anterior lobe contained a few MEAGL-immunoreactive cells but no nerve fibers. A previously unknown enkephalin-immunoreactive nerve fiber system was revealed in the intermediate lobe. These fibers originated in a dense MEAGL-immunoreactive plexus located along the border between the intermediate and posterior lobes and were distributed throughout the lobe. In the posterior lobe, MEAGL immunoreactivity was found in a very dense network of varicose fibers that was evenly distributed over the entire lobe. These results provide a morphological correlate for previous chemical studies and together with them suggest that MEAGL-immunoreactive innervation regulates endocrine functions of the intermediate and posterior lobes directly at the pituitary level.
Soinila
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Mark O. Hatfield Marine Science Center, Oregon State University, Newport.
Bäck
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N
Mpitsos
G J
GJ
D000818:Animals; D004744:Enkephalin, Methionine / Q000031:analogs & derivatives* / Q000032:analysis / Q000276:immunology; D005455:Fluorescent Antibody Technique; D008297:Male; D051379:Mice; D016253:Microscopy, Immunoelectron / Q000379:methods; D010902:Pituitary Gland / Q000737:chemistry* / Q000294:innervation; D051381:Rats; D012680:Sensitivity and Specificity; D014021:Tissue Preservation / Q000379:methods
D004744:Enkephalin, Methionine; C033453:enkephalin-Met, Arg(6)-Gly(7)-Leu(8)-