title: Differential effects of morphine and naltrexone on the in vitro LH secretion from male and female carp pituitary gland.
abstract: The in vitro effects of morphine (10(-10), 10(-8), 10(-6) or 10(-5) M) or/and naltrexone (10(-6) or 10(-8) M) on LH release from male and female carp (Cyprinus carpio L.) dispersed pituitary cells (obtained from fish at the time of late gonad recrudescence) were investigated. Morphine alone at the lowest tested concentration (10(-10) M) increased LH secretion from the cells of males. On the contrary, in female cell incubations the highest concentrations of morphine (10(-6) or 10(-5) M) significantly lowered LH levels. Naltrexone alone (at both tested concentrations) had no influence on LH secretion, neither in males nor in females. However in the incubations of female cells it antagonised the influence of morphine at 10(-10) or 10(-8) M. In male cell incubations naltrexone abolished the stimulatory action of morphine at 10(-10) M. The results suggest that in the in vitro culture of carp pituitary cells LH secretion is modulated by the opioids which affect the release of this gonadotropin through the typical opioid receptors and that the mu type of these receptors is involved in this process. The effects of opioid agonist and antagonist depend on the stage of gonadal maturity and the sex of fish i.e. the actual level of sex steroids.
authors.affiliation: Department of Ichthyobiology and Fisheries, University of Agriculture, ul. Prof. T. Spiczakowa 6, 30-199 Krakow-Mydlniki, Poland. msokmik@ar.krakow.pl
authors.forename: Miroslawa
authors.initials: M
authors.lastname: Sokolowska-Mikolajczyk
authors.forename: Magdalena
authors.initials: M
authors.lastname: Socha
authors.forename: Tomasz
authors.initials: T
authors.lastname: Mikolajczyk
authors.forename: Jaroslaw
authors.initials: J
authors.lastname: Chyb
authors.forename: Jerzy
authors.initials: J
authors.lastname: Szymacha
authors.forename: Piotr
authors.initials: P
authors.lastname: Epler
mesh_terms: D000818:Animals; D002347:Carps; D004305:Dose-Response Relationship, Drug; D005260:Female; D066298:In Vitro Techniques; D007986:Luteinizing Hormone / Q000378:metabolism*; D008297:Male; D009020:Morphine / Q000494:pharmacology*; D009271:Naltrexone / Q000494:pharmacology*; D009292:Narcotic Antagonists / Q000494:pharmacology*; D010902:Pituitary Gland / Q000187:drug effects* / Q000378:metabolism
chemical_list: D009292:Narcotic Antagonists; D009271:Naltrexone; D009020:Morphine; D007986:Luteinizing Hormone