8 mg of naloxone were administered IV to 14 normal volunteers in a placebo-controlled, double-blind experiment. Plasma levels of beta-endorphin, cortisol, prolactin, growth hormone, HVA and MHPG were determined before and 45 min after administration. Naloxone elicited significant increases in cortisol and MHPG but did not change plasma levels of the other compounds. In an additional experiment on two subjects, 20 mg of naloxone caused elevations of beta-endorphin as well as of cortisol. This parallel increase indicates that the linkage between the secretion of beta-endorphin and ACTH/cortisol may be dose-dependent. The increase in MHPG is in agreement with the hypothesized association of noradrenergic hyperactivity and opiate withdrawal.

The occurrence of free and conjugated dopamine was determined by HPLC in human caudate nucleus, hypothalamus, and kidney. Free norepinephrine and dihydroxyphenylacetic acid levels in some tissues were also determined. Conjugated dopamine was found to account for 25% of the total DA in the kidney. Conjugated DA accounted for 2.9% and 5.1% of the total DA in the caudate nucleus and hypothalamus, respectively. These results indicate that conjugated dopamine is not homogenously distributed in human tissue.

No abstract

No abstract

No abstract