Effect of gonadectomy on the concentrations of catecholamines in discrete areas of the diencephalon of the domestic fowl.
Concentrations of dopamine, noradrenaline and adrenaline in discrete areas of the diencephalon in male and female domestic fowl were correlated with changes in the plasma concentrations of LH induced by gonadectomy. Gonadectomized birds of both sexes exhibited raised plasma concentrations of LH and in castrated cockerels the daily administration of testosterone propionate was completely effective in preventing the postcastration rise in LH. Although no significant alterations in the brain concentrations of noradrenaline or adrenaline were observed in cockerels, the concentration of dopamine in the paraventricular nucleus (PVM), dorsomedial thalamic nucleus and mediobasal hypothalamus (MBH) were significantly raised in castrated compared with sham-operated birds by 136, 182 and 52% respectively. In each case the increase was partially suppressed by testosterone replacement therapy. In pullets, ovariectomy resulted in significant increases in the concentrations of dopamine (83%) and noradrenaline (78%) in the MBH and noradrenaline (35%) and adrenaline (34%) in the PVM. These findings suggest that in the fowl at least part of the negative feedback effect of gonadal steroids on LH secretion may be mediated by catecholaminergic mechanisms at the level of the hypothalamus.
D000818:Animals; D002369:Castration; D002645:Chickens; D004027:Diencephalon / Q000378:metabolism*; D004298:Dopamine / Q000378:metabolism*; D004837:Epinephrine / Q000378:metabolism*; D005260:Female; D007031:Hypothalamus / Q000378:metabolism; D007986:Luteinizing Hormone / Q000097:blood*; D008297:Male; D009638:Norepinephrine / Q000378:metabolism*
D007986:Luteinizing Hormone; D004298:Dopamine; D009638:Norepinephrine; D004837:Epinephrine