Dopamine decreases release of luteinizing hormone releasing hormone from superfused rat mediobasal hypothalamus.
The effects of dopamine hydrochloride (DA) on the releases of LHRH and LH were examined in a serial sequential double chamber perifusion system by perifusing the mediobasal hypothalamus including the preoptic area and/or pituitaries excised from diestrus female rats. DA, perifused at a dose of 4.2 X 10(-4) M, significantly (p less than 0.05) lowered LH secretion from the pituitary in series with the hypothalamus 40-80% below the preinfusion level, but it had no effect on LH efflux from the pituitary perifused alone. DA also significantly (p less than 0.05) reduced the LHRH level 20-40% below the initial level. Perifusion with the DA receptor blocker haloperidol at a concentration of 10(-6) M abolished the suppressive effect of DA on LH secretion. These findings indicate that DA suppressed hypothalamic LHRH release, resulting in decrease in LH secretion from the pituitary in diestrus rats.
D000818:Animals; D004298:Dopamine / Q000494:pharmacology*; D004971:Estrus; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism*; D007033:Hypothalamus, Middle / Q000187:drug effects / Q000378:metabolism*; D066298:In Vitro Techniques; D007986:Luteinizing Hormone / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains
D007987:Gonadotropin-Releasing Hormone; D007986:Luteinizing Hormone; D004298:Dopamine