Norepinephrine induces releases of both LH-RH from the hypothalamus and LH from the rat pituitary in vitro.
The effects of norepinephrine (NE) on the release of luteinizing hormone (LH) and LH-releasing hormone (LH-RH) were examined in a sequential double chamber perifusion system by perfusing the medio-basal hypothalamus (MBH) and/or pituitaries excised from normal female rats in diestrus. When the pituitary alone or in sequence with the MBH was perifused with medium containing 200 micrograms/ml of NE, the concentration of LH in the efflux was significantly (p less than 0.05) increased to the level 50-150% over the pre-injection control, whereas medium without NE had no effect. Perifusion of the pituitary in sequence with the MBH produced a higher peak level of LH than that attained by the perifusion of the pituitary alone. Administration of NE induced a significant increase in LH-RH release from the MBH, although the medium alone had no effect. These data suggest that NE induces LH release from the pituitary both by increasing LH-RH release from the MBH and by its direct action on the pituitary.
D000818:Animals; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism*; D007031:Hypothalamus / Q000378:metabolism*; D066298:In Vitro Techniques; D007986:Luteinizing Hormone / Q000378:metabolism*; D009638:Norepinephrine / Q000494:pharmacology*; D010902:Pituitary Gland / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains
D007987:Gonadotropin-Releasing Hormone; D007986:Luteinizing Hormone; D009638:Norepinephrine