L-tyrosine fails to potentiate several peripheral actions of the sympathomimetics

  title={L-tyrosine fails to potentiate several peripheral actions of the sympathomimetics},
  author={Keith M. Hull and Timothy J. Maher},
  journal={Pharmacology Biochemistry and Behavior},
  • K. Hull, T. Maher
  • Published 1 July 1991
  • Biology
  • Pharmacology Biochemistry and Behavior
4 Aromatic Amino Acids in the Brain
The abilities of the precursor amino acids, tryptophan and tyrosine, to control the rates at which neurons can produce and release their neurotransmitter products underlie a number of physiological processes, and also constitute a potential tool for amplifying or decreasing synaptic neurotransmission.
The effect of caffeine, green tea and tyrosine on thermogenesis and energy intake
Only caffeine was thermogenic in the given dose and caused no haemodynamic side effects, and the sample size was probably too small to detect any appetite suppressant properties of the treatments.
Dietary herbal supplements with phenylephrine for weight loss.
Pilot studies suggest phenylephrine is not efficacious for weight loss, although no toxicity was seen, and there were no significant safety issues in either study.
Body fat loss achieved by stimulation of thermogenesis by a combination of bioactive food ingredients: a placebo-controlled, double-blind 8-week intervention in obese subjects
The bioactive supplement increased 4-h thermogenesis by 90 kJ more than placebo, and the effect was maintained after 8 weeks and accompanied by a slight reduction in fat mass, which may support weight maintenance after a hypocaloric diet.


L-tyrosine potentiates the anorexia induced by mixed-acting sympathomimetic drugs in hyperphagic rats.
  • K. Hull, T. Maher
  • Biology, Chemistry
    The Journal of pharmacology and experimental therapeutics
  • 1990
Results indicate that L-TYR specifically potentiates the anorectic activity of the studied mixed-acting sympathomimetics and are consistent with the requirement of the central conversion of L- TYR to catecholamines via TYR hydroxylase for this response.
Cardiovascular differences between phenylpropanolamine and its related norephedrine isomers in the rat.
It is demonstrated that significant mechanistic differences exist between these norephedrine isomers in the cardiovascular system of the urethane:chloralose anesthetized rat.
Suppression of amphetamine-induced hypothermia by the neutral amino acid valine.
The observed effects of valine pretreatment support the hypothesis that treatments which alter precursor (tyrosine) availability also affect brain catecholamine synthesis.
Relationships between drug-induced changes in tetrahydrobiopterin and biogenic amine concentrations in rat brain.
Although some of the statistically significant changes in regional brain BH4 levels are small, previous reports of the failure of biopterin to change in response to more than 30 other central nervous system drugs, including such stimulants as methylphenidate and cocaine, makes them noteworthy.
Characteristics of Tyrosine Hydroxylase Activation by K+‐Induced Depolarization and/or Forskolin in Rat Striatal Slices
The data strongly support the concept that Ca2+– but not cyclic AMP‐dependent phosphorylation is responsible for TH activation in depolarized dopaminergic terminals.
Influence of dl-phenylpropanolamine on brown adipose tissue thermogenesis in the adult rat
Control rats exhibited stable IBAT and rectal temperatures prior to and after saline injection, whereas PPA-treated rats exhibited in-creases in IBAT temperature and, after a 10-15-min lag, in rectal temperature, which may help explain the weight-reducing effect of PPA.