YAZDANPARAST R, QUJEQ D. SIGNIFICANT CHANGES IN THE ACTIVITY OF GABATRANSAMINASE AND SUCCINATE SEMIALDEHYDE DEHYDROGENASE OF MOUSE HYPOTHALAMUS FOLLOWING PERIPHERAL INJECTION OF CHOLECYSTOKININ-8 AND/OR CAERULEIN. Med J Islam Repub Iran 1994; 7 (4) :263-268
URL:
http://mjiri.iums.ac.ir/article-1-1419-en.html
From the Institute of Biochemistry and Biophysics, University of Tehran
Abstract: (4370 Views)
The activities of 4-aminobutyric-2-oxoglutaric acid transaminase (GABA-T)
and succinate semialdehyde dehydrogenase (SSADH) were determined in mouse
hypothalamus after peripheral injections of cholecystokinin-8 (CCK-X)and/or
caerulein (CLN). GABA transaminase activity was measured utilizing endogenous
succinate semialdellyde dehydrogenase to convert the product of GAB A-T, succinate
semialdehyde, to succinate. The concurrently formed NADH was used as an estimate
of GABA-T activity. Similarly, the activity of SSADH was determined in terms of
NADH. Injection of CCK-8 and/or CLN inhibited the GABA-T and SSADH
activities in dose-dependent responses. The activities of GAB A-Tand SSADH were
diminished by 52 and 66 percent respectively, 30 minutes after injection of CCK-8
(50 µg/kg body weight).Similarly, peripheral injection of CLN (50 µg/kg body
weight) reduced the activity of GABA-T and SSADH by 56 and 65 percent
respectively, in 30 minutes. Using ill vitro models, the full activities of GABA-T and/
or SSADH, after incubation with CCK-8 and/or CLN, were restored following 30
hours of dialysis at 4°C. These results indicate direct and reversible interactions
between the catabolizing enzymes of GABA (GABA-T and SSADH) and the
peptides CCK-8 and CLN.