Guggulsterone induced changes in the levels of biogenic monoamines and dopamineβ-hydroxylase activity of rat tissues

1986 ◽  
Vol 10 (1) ◽  
pp. 15-19 ◽  
Author(s):  
Madhulika Srivastava ◽  
Narinder K. Kapoor
Keyword(s):  
Rat Tissues ◽  
Hydroxylase Activity ◽  
Biogenic Monoamines ◽  
Induced Changes

Stress-induced changes in in vivo and in vitro dopamine-β-hydroxylase activity in spontaneously hypertensive rats

1982 ◽  
Vol 28 (3) ◽  
pp. 340-346 ◽  
Author(s):  
Keisuke Fujita ◽  
Ryoji Teradaira ◽  
Takashi Inoue ◽  
Hisahide Takahashi ◽  
Hidehiro Beppu ◽  
...  
Keyword(s):  
Spontaneously Hypertensive Rats ◽  
Hypertensive Rats ◽  
Hydroxylase Activity ◽  
Spontaneously Hypertensive ◽  
Induced Changes

scholarly journals The regulation of phenylalanine hydroxylase in rat tissues in vivo. Substrate- and cortisol-induced elevations in phenylalanine hydroxylase activity

1976 ◽  
Vol 154 (3) ◽  
pp. 619-624 ◽  
Author(s):  
O Greengard ◽  
J A. Delvalle
Keyword(s):  
Phenylalanine Hydroxylase ◽  
Enzyme Concentration ◽  
Rat Tissues ◽  
Hydroxylase Activity ◽  
Adult Rats ◽  
No Inhibition ◽  
Hormonal Induction ◽  
Positive Regulators

Injections of phenylalanine increased a 2.5-fold in 9 h the hepatic phenylalanine hydroxylase activity of 6-day-old or adult rats that had been pretreated (24h earlier) with p-chlorophenylalanine; without such pretreatment, phenylalanine did not raise the enzyme concentration. This difference is paralleled by the much greater extent to which the injected phenylalanine accumulated in livers of the pretreated compared with the normal animals. The hormonal induction of hepatic phenylalanine hydroxylase activity obeyed different rules: an injection of cortisol was without effect on adult livers but caused a threefold rise in phenylalanine hydroxylase activity of immature ones, both without and after pretreatment with p-chlorophenylalanine. In the latter instance, the effects of cortisol, and of phenylalanine were additive. Actinomycin inhibited the cortisol- but not the substrate-induced increase of phenylalanine hydroxylase, whereas puromycin inhibited both. The results indicate that substrate and hormone, two potential positive regulators of the amount of the hepatic (but not the renal) phenylalanine hydroxylase, act independently by two different mechanisms. The negative effector, p-chlorophenylalanine, also appears to interact with the synthetic (or degradative) machinery rather than with the existing phenylalanine hydroxylase molecules: 24h were required in vivo for an 85% decrease to ensue, and no inhibition occurred in vitro when incubating the enzyme with p-chlorophenylalanine or with liver extracts from p-chlorophenylalanine-treated rats.

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