In vitro effect of adrenocorticotrophic hormone on the pH profile of tri- and diester lipase activities from rat brain.
The influence of adrenocorticotrophic hormone (ACTH) on the hydrolysis of tri- and dioleoylglycerol by a cerebral lipase was studied using a synaptosomal preparation from rat brain as source of enzyme. When ACTH was added to the lipolytic medium, it caused a marked shift of the optimum pH values of catalysis towards alkaline values. In the pH range 5.8-6.5, these shifts resulted in reaction rates 5- to 20-fold higher, depending on the experimental conditions, than those measured without hormone. The ACTH effect was dependent on the NH2-terminal sequence extending through the amino acid residues 15-18. The results suggest that the hormonal influence is specific and mediated through a colipase-like effect.
D000324:Adrenocorticotropic Hormone / Q000494:pharmacology*; D000818:Animals; D001921:Brain / Q000201:enzymology*; D004075:Diglycerides / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008049:Lipase / Q000378:metabolism*; D008297:Male; D051381:Rats; D013574:Synaptosomes / Q000201:enzymology; D014304:Triolein / Q000378:metabolism
D004075:Diglycerides; D014304:Triolein; D000324:Adrenocorticotropic Hormone; D008049:Lipase; C013965:diolein