Effect of three different modes of alcohol administration on the activity of the rat hypothalamic-pituitary-adrenal axis.
The present study compared the effect of different modes of alcohol administration on the activity of the hypothalamic-pituitary-adrenal (HPA) axis. In a first series of studies, we investigated the influence of the intraperitoneal (ip) and intragastric (ig) effect of acutely administered alcohol. Over a 3-hr period, alcohol induced dose-related increases in adrenocorticotropic hormone (ACTH) and alcohol levels in the circulation. There was a good correlation between blood ACTH and alcohol levels (ip treatment, R = 0.84; ig treatment, R = 0.79). Measurement of steady-state mRNA of the immediate early gene NGFI-B, taken as an index of neuronal activation in the paraventricular nucleus (PVN) of the hypothalamus of rats administered 3 g of alcohol/kg, indicated significant (p < 0.01) increases between 60 and 180 min after both ip and ig alcohol injection, with peak stimulation at 1 and 2 hr, respectively. Although NGFI-B mRNA levels had returned to control level in the parvicellular portion of the PVN of animals administered the drug ip 4 hr earlier, they were still significantly (p < 0.01) elevated 4 hr after ig treatment. A second series of studies used rats fed an alcohol diet containing 6.4% alcohol (w/v), or pair-fed. The rats were tested during the 4th or 6th night of treatment. Despite blood alcohol levels ranging between 0.060 and 0.140% w/v, there was no significant rise in plasma ACTH/corticosterone levels in animals fed the drug, and no detectable NGFI-B mRNA in their PVN. Collectively, these results indicate that both the ip and the ig acute injection of alcohol induced dose-related increases in plasma ACTH levels. PVN neuronal activation was also observed. In contrast, the alcohol diet had no effect on HPA hormone levels or PVN expression of NGFI-B.
Ogilvie
K
K
Clayton Foundation Laboratories for Peptide Biology, Salk Institute for Biological Studies, La Jolla, CA 92037, USA.
Lee
S
S
Rivier
C
C
D000284:Administration, Oral; D000324:Adrenocorticotropic Hormone / Q000097:blood*; D000428:Alcohol Drinking / Q000009:adverse effects; D000818:Animals; D003345:Corticosterone / Q000097:blood*; D000431:Ethanol / Q000008:administration & dosage* / Q000493:pharmacokinetics / Q000494:pharmacology; D007030:Hypothalamo-Hypophyseal System / Q000187:drug effects*; D007274:Injections, Intraperitoneal; D008297:Male; D010286:Paraventricular Hypothalamic Nucleus / Q000187:drug effects; D010913:Pituitary-Adrenal System / Q000187:drug effects*; D051381:Rats; D017207:Rats, Sprague-Dawley; D009435:Synaptic Transmission / Q000187:drug effects
D000431:Ethanol; D000324:Adrenocorticotropic Hormone; D003345:Corticosterone