Plasma corticosteroid levels in rats maintained on a long-acting naltrexone delivery system.
A long-acting delivery system for naltrexone has been described, which blocked the antinociceptive action of 10 mg kg-1 s.c. dose of morphine in rats for a period of 2 to 3 months. Male Wistar rats implanted s.c. with such a delivery system showed highly significant depression of plasma corticosteroid levels (40.2% in one week and 22.4 to 27.2% in 3 months) as compared to placebo pellet-implanted animals. Morphine-dependent male rats implanted with 75 mg morphine pellets showed a small (17.5%) but significant increase in plasma corticosteroid levels as compared to the placebo controls 72 hr. after pellet implantation.
D000305:Adrenal Cortex Hormones / Q000097:blood*; D000818:Animals; D004343:Drug Implants; D008297:Male; D009020:Morphine / Q000037:antagonists & inhibitors; D009270:Naloxone / Q000031:analogs & derivatives*; D009271:Naltrexone / Q000008:administration & dosage / Q000494:pharmacology*; D051381:Rats; D011930:Reaction Time / Q000187:drug effects; D013997:Time Factors
D000305:Adrenal Cortex Hormones; D004343:Drug Implants; D009270:Naloxone; D009271:Naltrexone; D009020:Morphine