Leumorphin, a novel opioid peptide, promotes lordosis in female rats.
The actions of leumorphin, a recently characterized endogenous opioid peptide, oppose of most opioid peptides in facilitating lordosis reflex, a major component of female sexual behavior in the rat. Maximal lordosis appeared promptly after infusion of 1 nmol leumorphin into the ventromedial hypothalamus of ovariectomized estrogen-primed rats. This facilitation lasted for as long as 5 h, unless interrupted by midbrain infusion of an antiserum to prolactin. The result is a discovery of a novel substance of remarkable strength in facilitating lordosis, an effect presumably mediated by midbrain release of prolactin.
D000818:Animals; D004357:Drug Synergism; D004745:Enkephalins / Q000494:pharmacology*; D004958:Estradiol / Q000494:pharmacology; D005260:Female; D006065:Gonadotropins, Pituitary / Q000502:physiology; D010052:Ovariectomy; D010487:Periaqueductal Gray / Q000187:drug effects*; D011187:Posture; D011498:Protein Precursors / Q000494:pharmacology*; D051381:Rats; D012726:Sexual Behavior, Animal / Q000187:drug effects*; D013268:Stimulation, Chemical; D014697:Ventromedial Hypothalamic Nucleus / Q000187:drug effects*
D004745:Enkephalins; D006065:Gonadotropins, Pituitary; D011498:Protein Precursors; D004958:Estradiol; C033660:preproenkephalin