5 The Biosynthesis and Metabolism of the Catecholamines

Sandler, M.; Ruthven, C.R.J.

doi:10.1016/s0079-6468(08)70199-1

Cited by 27 publications

(7 citation statements)

References 622 publications

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“…high u-HVA associated with Red and low u-HVA with Aug. Several studies have reported on the origin of the HVA excreted in urines. Although the kidneys contain the enzymes necessary for the degradation of renal dopamine [Sandler and Ruthven, 1969]. the renal dopamine is excreted in the form of dopamine and not of HVA [Cuche et al.…”

Section: Discussionmentioning

confidence: 99%

Frontal Auditory-Evoked Potential Augmenting-Reducing and Urinary Homovanillic Acid

Bruneau¹,

Barthélémy²,

Jouve³

et al. 1986

Neuropsychobiology

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Relationships between augmenting-reducing (Aug/Red) in auditory modality and dopaminergic metabolism were investigated in young adults with respect to sex. The slope values of evoked potential amplitude changes with increasing intensities were used to evaluate Aug/Red both at Cz and Fz for each of the five components: PI, Nl, P2, P1N1, N1P2. The greatest slopes (Aug) were found in females. Individual differences in dopaminergic metabolism were estimated by assaying free and conjugated forms of homovanillic acid (HVA) in urines. HVA excretion rates were significantly more variable in males than in females. Relationships between Aug/Red and HVA levels were only found in males. The lower the Aug/Red slopes recorded at Fz site for the Nl component (weak augmenter or reducer responses), the higher the urinary HVA level and particularly the conjugated forms of HVA. These results are of interest for further applications in psychopathology.

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Section: Discussionmentioning

confidence: 99%

Frontal Auditory-Evoked Potential Augmenting-Reducing and Urinary Homovanillic Acid

Bruneau¹,

Barthélémy²,

Jouve³

et al. 1986

Neuropsychobiology

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“…These two metabolites may be subsequently inactivated t o 4-hydroxy-3-methoxymandelic acid (VMA). [26][27][28][29][30][31][32][33][34][35] there is significant extracerebral metabolism of it. This extracerebral metabolism of exogenously administered dopa is therapeutically wasteful, on one hand yielding inactive metabolites, such as VMA, HVA, and dihydroxyphenylacetic acid (dopac).…”

Section: Urinementioning

confidence: 99%

METABOLISM AND ABSORPTION OF l‐3,4 DIHYDROXYPHENYLALANINE IN PATIENTS WITH PARKINSON'S DISEASE

Bianchine

Calimlim

Morgan

et al. 1971

Annals of the New York Academy of Sciences

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“…Tyrosine is essential for the production of melanin pigments, and levels of pigmentation in cultured melanocytes depend on tyrosine concentration (Hirobe et al 2002(Hirobe et al , 2003. Tyrosine, a non-essential amino acid, can be derived from the essential amino acid phenylalanine, which is usually readily hydroxylated to form tyrosine by phenylalanine hydroxylase (Sandler & Ruthven, 1969). In childhood malnutrition the combination of marginal or deficient intake and infection is common and might create an increased requirement for aromatic amino acids.…”

Section: Discussionmentioning

confidence: 99%

Childhood malnutrition is associated with a reduction in the total melanin content of scalp hair

et al. 2007

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Childhood malnutrition is known to be associated with visible lightening of hair colour (hypochromotrichia). Nevertheless, no systematic investigations have been carried out to determine the biochemical basis of this change. We used an HPLC method to measure melanins in the scalp hair of thirteen Jamaican children, diagnosed as having primary malnutrition, during various stages of their treatment and after recovery. During treatment for malnutrition, a progressive decrease in total melanin content along the hair shaft from tip to root (root:tip ratio: 0·62 (sd 0·31)) was observed. This ratio was significantly different (P = 0·003) from the ratio observed among children sampled several months after discharge from hospital (0·93 (sd 0·23)) and among normal control children (0·97 (sd 0·12)). Thus, it appears that a decrease in melanin content is associated with periods of malnutrition. The low root:tip ratio during malnutrition presumably arises because the tips reflect prior hair growth during ‘normal’ nutrition and the roots reflect hair growth during malnutrition; a return of the root:tip ratio to that seen among controls reflects ‘recovery’ from malnutrition. It is possible that reduced intake or availability of tyrosine, a key substrate in melanin synthesis, may play a role in the reduction of hair melanin content during periods of malnutrition. The precise mechanisms by which melanin content is reduced, and the role of aromatic amino acid availability in hair colour change and other features of childhood malnutrition remain to be explored.

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5 The Biosynthesis and Metabolism of the Catecholamines

Cited by 27 publications

References 622 publications

Frontal Auditory-Evoked Potential Augmenting-Reducing and Urinary Homovanillic Acid

Frontal Auditory-Evoked Potential Augmenting-Reducing and Urinary Homovanillic Acid

METABOLISM AND ABSORPTION OF l‐3,4 DIHYDROXYPHENYLALANINE IN PATIENTS WITH PARKINSON'S DISEASE

Childhood malnutrition is associated with a reduction in the total melanin content of scalp hair

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