Endocrine responses to the oral ingestion of a physiological dose of essential amino acids in humans

Abstract

The response of insulin, human growth hormone (hGH), cortisol, leptin and ghrelin, in addition to various metabolic parameters, was measured at 10 minute intervals following the oral ingestion of a standardised physiological dose of essential amino acids (AA). Twenty-eight healthy male, fasted volunteers (aged 18-40 yrs, BMI 18·0-24·5 kg/m 2 ) took part in the study; 13 volunteers in the AA group, nine subjects in an iso-caloric control group, and a further six subjects served as fasting controls.Twenty minutes after ingestion, insulin reached peak concentrations that were up to 500% higher than basal values (P,0·0001). The AA group and iso-caloric control group showed a similar insulin response.AA ingestion led to an increase in hGH secretion with maximum concentrations being 2100 1013% higher than the basal values (P,0·0001). In contrast, no changes in hGH concentrations were observed in the iso-caloric controls; in the fasting controls only a slight increase in hGH was found towards the end of the fasting period.While cortisol decreased significantly (P,0·01) during the study in the AA group, neither control group showed a significant change in this parameter.Changes in leptin levels remained insignificant in all three groups, whereas ghrelin showed a different profile in each of the three groups, i.e. a continuous rise towards the end of the study period (P,0·001) in the AA group, a less significant effect for the fasting group, and no effect at all in the iso-caloric control group.There was no significant correlation between the concentrations or the area under curve of the hormones measured in any of the groups.The endocrine data provided in this study indicate that a single bolus of essential AA in fasted individuals is associated with both anabolic and catabolic hormonal responses.

The relation between cortisol and functional connectivity in people with and without stress‐sensitive epilepsy

“…To avoid contamination of saliva, subjects were asked to rinse their mouth with water 5 min before sampling after any food intake. 23 Salivettes were stored at À9°C for one to 4 days, after which they were centrifuged for 10 min at 3000 rpm. Storage until further analysis was at À20°C.…”

Expressão gênica de IGF-I e GHR no fígado e no músculo do peito de codornas de corte suplementadas com diferentes níveis de metionina em duas gerações sucessivas

“…Alguns estudos mostram que aves recebendo dieta deficiente em metionina apresentaram menor crescimento (Carew et al, 2003). Muitos autores têm mostrado relação entre administração de aminoácidos como a metionina e a secreção de GH (Groschl et al, 2003;Collier et al, 2005), e, ainda, que o desempenho mediado pela ação do IGF-I também pode ser influenciado pela suplementação da metionina. Neste estudo, como se pode observar na Tab.…”

Estimation of gastric ghrelin-positive cells activity in hyperthyroid rats.

“…In humans, circulating ghrelin levels are increase by energy restriction and decrease by food intake indicating that ghrelin secretion is mostly regulated by metabolic signals [32]. Gastric ghrelin mRNA expression in rats has been increased by a high-fat diet [33], although the oral, intravenous or intragastric administration of fat has also been shown to decrease circulating ghrelin levels [34].…”

“…Gastric ghrelin mRNA expression in rats has been increased by a high-fat diet [33], although the oral, intravenous or intragastric administration of fat has also been shown to decrease circulating ghrelin levels [34]. Similarly, oral protein administration has been reported to increase plasma ghrelin levels by some authors [32,35] or to decrease them according to others [34]. In humans, constant lipid infusion has been reported not to influence plasma ghrelin levels [30], whereas oral fat administration has been reported to decrease, although to a lesser extent than after glucose ingestion [36,37] or even to increase circulating ghrelin levels [38].…”