Acetyl-L-carnitine effect on pituitary and plasma beta-endorphin responsiveness to different chronic intermittent stressors.
The aims of the present study were: 1) to compare the effect of two different chronic intermittent stressors i.e. cold-swimming versus ether, on the pituitary opioidergic system; 2) to evaluate the response of pituitary and plasma beta-endorphin (beta-EP) to an acute stress in chronically stressed rats; and 3) to evaluate the effect of acetyl-l-carnitine treatment (10 mg/day/rat per os at night) on pituitary and plasma beta-EP changes induced by two different types of chronic stress. The stressors were applied twice a day for 10 days. Rats were killed either before, during or after the last swimming or ether stress session. beta-EP was measured by radioimmunoassay in anterior pituitary and in neurointermediate lobe extracts and in plasma. The following observations were made: 1) Chronic intermittent cold-swimming stress increased anterior pituitary contents and plasma beta-EP levels; 2) both chronic intermittent cold-swimming stress and ether stress caused an increase of neurointermediate lobe beta-EP contents; 3) as in control animals, rats exposed to chronic intermittent swimming stress reduced pituitary beta-EP contents and raised plasma beta-EP levels in response to the last acute swimming stress; 4) in contrast to control animals, rats exposed to chronic intermittent ether stress did not show any significant response of the pituitary-plasma opioidergic system to the last acute ether session; 5) the acetyl-l-carnitine treatment counteracted the changes evoked by chronic intermittent cold-swimming stress on the pituitary and plasma beta-EP levels.(ABSTRACT TRUNCATED AT 250 WORDS)
Bidzinska
B
B
Department of Endocrinology, Medical School of Wroclaw, Poland.
Petraglia
F
F
Angioni
S
S
Genazzani
A D
AD
Criscuolo
M
M
Ficarra
G
G
Gallinelli
A
A
Trentini
G P
GP
Genazzani
A R
AR
D000108:Acetylcarnitine / Q000494:pharmacology*; D000818:Animals; D002908:Chronic Disease; D003080:Cold Temperature; D004986:Ether / Q000633:toxicity; D008297:Male; D010902:Pituitary Gland / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D013315:Stress, Psychological / Q000378:metabolism*; D013550:Swimming; D001615:beta-Endorphin / Q000096:biosynthesis* / Q000097:blood
D004986:Ether; D001615:beta-Endorphin; D000108:Acetylcarnitine