NORADRENALINE CONTENT AND RELEASE IN MALE AND FEMALE RAT TAIL ARTERIES

In tail-artery segments isolated from male and female control and gona dectomized rats, noradrenaline content and noradrenaline released by e lectrical stimulation were measured by high-pressure liquid chromatogr aphy. Noradrenaline content, expressed as a function of tissue wet wei ght, was higher in tail arteries from female than from male rats, but there were no significant differences between control and orchiectomiz ed males or control and ovariectomized females. Electrical stimulation of vascular segments in the presence of cocaine (10(-5) M) and deoxyc orticosterone (10(-5) M) induced release of noradrenaline that was inc reased in the presence of the alpha(2)-adrenergic antagonist idaxozan (10(-6) M). However, no differences were found in either basal or stim ulation-evoked fractional noradrenaline release between male or female , control or gonadectomized animals. These results indicate that contr ol of noradrenaline release at the nerve ending does not appear to be different between genders. There may be differences in adrenergic dens ity, but noradrenaline content does not appear to be modified by circu lating gonadal hormones.