Distribution of opioid peptides in the pituitary: a new hypothalamic-pars nervosa enkephalinergic pathway.
The distribution of the endorphins, beta-endorphin and enkephalin (Met5-enkephalin and Leu5-enkephalin), was determined in the pars distalis, intermedia, and nervosa of the rat pituitary using both immunocytochemical and radioimmunological methods. Immunoreactive (ir) beta-endorphin was found in pars distalis and pars intermedia. On gel filtration of the pars distalis extracts, beta-endorphin immunoreactivity was eluted in three peaks corresponding to pro-opiocortin (5%), beta-lipotropin (75%), and beta-endorphin (20%). beta-Endorphin was the only component in the pars intermedia. Enkephalin was found in high amount in the pars nervosa. A new enkephalinergic hypothalamic-pars nervosa pathway was observed. Dehydration experiments on normal rats and analysis of the genetically polyuric Brattleboro rat suggest that this enkephalinergic pathway may modulate neurohypophyseal neurosecretion.
D000818:Animals; D004723:Endorphins / Q000378:metabolism*; D004745:Enkephalins / Q000378:metabolism; D007030:Hypothalamo-Hypophyseal System / Q000378:metabolism; D007031:Hypothalamus / Q000378:metabolism*; D009074:Melanocyte-Stimulating Hormones / Q000378:metabolism; D009434:Neural Pathways / Q000378:metabolism; D018377:Neurotransmitter Agents / Q000378:metabolism; D010902:Pituitary Gland / Q000378:metabolism*; D010904:Pituitary Gland, Posterior / Q000378:metabolism; D010909:Pituitary Hormones, Posterior / Q000378:metabolism; D011141:Polyuria / Q000378:metabolism; D051381:Rats; D014667:Vasopressins / Q000378:metabolism
D004723:Endorphins; D004745:Enkephalins; D018377:Neurotransmitter Agents; D010909:Pituitary Hormones, Posterior; D014667:Vasopressins; D009074:Melanocyte-Stimulating Hormones