Experimental alterations of endorphin levels in rat pituitary.
Endorphin (END) levels in rat pituitary were assessed with the opiate receptor binding assay. Procedures reported to alter hormone secretion from END-rich intermediate or anterior lobes were examined for their effect on END content. Lesions of the paraventricular nucleus (PVN) had no significant effect on END content. Ingestion of 2% NaCl reduced END levels in a significant majority of the animals. Suckling, a natural physiological stimulus, significantly elevated neurointermediate lobe END. Footshock and immobilization each evoked 40--50% reductions in anterior lobe END content. Pituitary ENDs are thus affected by many of the same stimuli that also promote release of a number of peptide hormones derived from the same biosynthetic precursor. However, separate mechanisms likely exist for control of secretion of these peptides from anterior and neurointermediate lobe.
D000818:Animals; D004597:Electroshock; D004723:Endorphins / Q000032:analysis*; D005260:Female; D007774:Lactation; D008297:Male; D009074:Melanocyte-Stimulating Hormones / Q000032:analysis; D010286:Paraventricular Hypothalamic Nucleus / Q000502:physiology; D010902:Pituitary Gland / Q000032:analysis*; D011247:Pregnancy; D051381:Rats; D012149:Restraint, Physical; D012965:Sodium Chloride / Q000008:administration & dosage; D013312:Stress, Physiological / Q000378:metabolism
D004723:Endorphins; D012965:Sodium Chloride; D009074:Melanocyte-Stimulating Hormones