Effects of ACTH 1-24 on hydrolysis of beta-casomorphin-4-nitroanilide in brain homogenates in vivo and in vitro.
Administration of ACTH 1-24 to 3-10 days old rats produced a significant decrease in hydrolysis of beta-casomorphin-4-nitroanilide (beta-CM-4NA) in the cytosolic fraction of brain homogenate in the first three hours after injection. Corticosterone treatment did not modify the hydrolysis of the substrate. ACTH 1-24 but not ACTH 4-10, Met-enkephalin or Leuenkephalin given to the brain homogenate resulted in a dose-dependent decrease in liberation of 4NA from beta-CM-4NA. Kinetic data suggest competitive inhibition of ACTH molecule on hydrolysis of beta-CMA-4NA. The ACTH treatment, however, did not influence the hydrolysis of Pro-Gly-4NA or Pro-Pro-4NA in the brain homogenate in vitro.
Endröczi
E
E
Institute of Clinical and Experimental Laboratory Investigations, Postgraduate Medical University, Budapest, Hungary.
Sasváry
M
M
Walentin
S
S
Simon
J
J
D000818:Animals; D001923:Brain Chemistry / Q000187:drug effects; D003345:Corticosterone / Q000494:pharmacology; D003366:Cosyntropin / Q000494:pharmacology*; D004723:Endorphins / Q000032:analysis / Q000187:drug effects / Q000378:metabolism*; D004743:Enkephalin, Leucine / Q000494:pharmacology; D004744:Enkephalin, Methionine / Q000494:pharmacology; D006868:Hydrolysis / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar
D004723:Endorphins; C092465:beta-casomorphin-4-nitroanilide; D003366:Cosyntropin; D004744:Enkephalin, Methionine; D004743:Enkephalin, Leucine; D003345:Corticosterone