Plasma concentrations and tissue uptake of free amino acids in dogs in sepsis and starvation: Effects of glucose infusion — Some effects of low alimentation

N, Vaidyanath; Birkhahn, Ronald H.; Border, John R.; Oswald, Garret; Trietley, Gregory; Yuan, Tran Fu; Moritz, E.; McMenamy, Rapier H.

doi:10.1016/0026-0495(78)90002-1

Cited by 7 publications

(1 citation statement)

References 15 publications

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“…To illustrate this, we performed phenylalanine challenge experiments on two rats that, in contrast to those employed in the above study, were not food-restricted, likely causing their metabolic status to differ. 49,50 Upon intravenous injection of a bolus 100 mg/kg of phenylalanine, the peak plasma concentrations, distribution half-lives, and elimination half-lives we determined are similar to those we observed for fasted animals (Figure 5; see also Table 1). Given that short-term food restriction is not thought to alter the activity or level of phenylalanine hydroylase, 51 this is perhaps to be expected.…”

Section: ■ Results and Discussionsupporting

confidence: 79%

Seconds-Resolved, In Situ Measurements of Plasma Phenylalanine Disposition Kinetics in Living Rats

2021

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Current knowledge of the disposition kinetics of endogenous metabolites is founded almost entirely on poorly time-resolved experiments in which samples are removed from the body for later, benchtop analysis. Here, in contrast, we describe real-time, seconds-resolved measurements of plasma phenylalanine collected in situ in the body via electrochemical aptamer-based (EAB) sensors, a platform technology that is independent of the reactivity of its targets and thus is generalizable to many. Specifically, using indwelling EAB sensors, we have monitored plasma phenylalanine in live rats with a few micromolar precision and a 12 s temporal resolution, identifying a large-amplitude, few-seconds phase in the animals’ metabolic response that had not previously been reported. Using the hundreds of individual measurements that the approach provides from each animal, we also identify inter-subject variability, including statistically significant differences associated with the feeding status. These results highlight the power of in vivo EAB measurements, an advancement that could dramatically impact our understanding of physiology and provide a valuable new tool for the monitoring and treatment of metabolic disorders.

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Section: ■ Results and Discussionsupporting

confidence: 79%