Περίληψη:
Patients with phenylketonuria (PKU) have a diet-controlled deficiency in
the conversion of phenylalanine (Phe) to tyrosine (Tyr), leading to
decreased production of noradrenaline, adrenaline, and dopamine. Poor
diet control results in high plasma Phe and low plasma Tyr and
catecholamine concentrations. Ghrelin, a recently described
gastrointestinal hormone that is elevated in the fasting state and low
in the fed state, is considered a major appetite-stimulating hormone,
possibly involved in the generation of obesity and insulin resistance.
We evaluated morning preprandial plasma ghrelin levels in 14
diet-controlled and 15 poorly controlled PKU patients and 20 age- and
body mass index (BMI)-matched healthy children ( controls) and
correlated its concentrations with those of Phe and catecholamines as
well as with their BMI and 24-h nutrient intake. Plasma ghrelin levels
were measured by RIA, plasma catecholamine concentrations were
determined by HPLC with electrochemical detection, and Phe and Tyr
levels were measured in an amino acid analyzer. The ghrelin
concentration ( 744 +/- 25 ng/liter) in diet-controlled patients did not
differ from that in controls ( 802 +/- 26 ng/liter; P > 0.05). On the
contrary, the ghrelin concentration was significantly reduced in poorly
controlled patients ( 353 +/- 23 ng/liter; P < 0.0001). Ghrelin
correlated negatively with Phe in all three groups, whereas it
correlated positively with catecholamine levels and energy intake and
negatively with BMI only in diet-controlled patients and controls. We
conclude that ghrelin secretion may receive positive direct or indirect
input from catecholamines. The absence of a correlation between ghrelin
and catecholamines, energy intake, or BMI in PKU patients on an
inadequate diet may be due to dysregulation of their neuroendocrine
system and might be affected by high Phe levels in the stomach and/or
central nervous system.
Συγγραφείς:
Schulpis, KH
Papassotiriou, I
Vounatsou, M
Karikas, GA and
Tsakiris, S
Chrousos, GP
