Enrichment in Urinary Ammonia and Urea with Hourly Oral Doses of [15N]glycine: Evidence for a Step Function and a Circadian Rhythm in Protein Turnover

Jackson, Alan A.; Soares, Mário J.; Grove, Grace; Waterlow, J. C.

doi:10.1042/cs0930265

Cited by 7 publications

(6 citation statements)

References 16 publications

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“…This conclusion was drawn from the rise of the ammonia isotopic enrichment to a second plateau during a hourly administration of 15 N-glycine along with food over 30 h (Jackson et al, 1997). Similar isotopic enrichment of leucine among periods in the present study do not support this conclusion.…”

Section: Nah 13 Co 3 Kineticscontrasting

confidence: 53%

“…In contrast, there is some evidence in humans of a circadian rhythm in protein degradation (Jackson et al 1997). This conclusion was drawn from the rise of the ammonia isotopic enrichment to a second plateau during a hourly administration of 15 N-glycine along with food over 30 h (Jackson et al, 1997).…”

Section: Nah 13 Co 3 Kineticsmentioning

confidence: 99%

“…In rats allowed free access to an adequate diet, there appeared to be only a small diurnal variation in muscle protein synthesis (Reeds et al 1986). In humans fed every hour, however, evidence of a circadian rhythm in protein degradation was reported (Jackson et al 1997).…”

mentioning

confidence: 99%

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Whole-body protein synthesis in growing barrows: diurnal and day-to-day variation and the effect of site of tracer infusion and sampling

Roy¹,

Lapierre²,

Estrada³

et al. 1998

Can. J. Anim. Sci.

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. 1998. Whole-body protein synthesis in growing barrows: diurnal and dayto-day variation and the effect of site of tracer infusion and sampling. Can. J. Anim. Sci. 78: 575-585. In the first experiment, two catheters were placed in one of three sites for infusion and sampling (vena cava and vena cava with 7 cm between catheter tips, VC/VC, n = 5; right ventricle and atrium, RV/RA, n = 5; anterior aorta and left ventricle, AA/LV, n = 4) to determine the effect of site on the measurement of CO 2 and leucine kinetics. Pigs received a 6-h continuous i.v. infusion of NaH 13 CO 3 (1.45 µmol h -1 kg -1 , preceded by a priming dose of 2.05 µmol kg -1 ) and of L[1-13 C]leucine (9.7 µmol h -1 kg -1 , preceded by a priming dose of 9.7 µmol kg -1 ), the following day. No effect (P > 0.10) of site was observed on NaH 13 CO 3 recovery rate, leucine irreversible loss rate (leucine ILR) and leucine used for protein synthesis (LS). A tendency (P < 0.10) for increased leucine oxidation (LO) was observed with the VC/VC compared to the RV/RA sites. In the second experiment, six growing barrows with catheters in the VC/VC site were infused as earlier with NaH 13 CO 3 and L[1-13 C]leucine for three different 6h periods (12:00 to 18:00 h, first day; 20:00 to 02:00 h, night; 12:00 to 18:00 h, second day) to determine the diurnal and day-to-day variation of CO 2 and leucine kinetics. No effect (P > 0.10) of period was observed on NaH 13 CO 3 recovery rate, leucine ILR and LS. The LO was lower (P < 0.05) on the second day compared with the first day (day-to-day variation) while similar (P > 0.10) LO was observed between the first day and night (diurnal variation). Together, these results indicate that 1) the VC/VC site can be used for L[1-13 C]leucine and NaH 13 CO 3 infusions, 2) NaH 13 CO 3 recovery studies can be performed either the day preceding or following the measurement of substrate and 3) protein synthesis estimated from a 6-h infusion period can be extrapolated to the 24 h periods under conditions of frequent feeding.Key words: Pigs, leucine, protein synthesis, tracer techniques, diurnal variation Roy, N., Lapierre, H., Estrada, R. et Bernier, J. F. 1998. Synthèse protéique de l'organisme entier chez les porcs en croissance: variation diurne, quotidienne et l'effet de sites d'infusion et de prélèvement du traceur. Can. J. Anim. Sci. 78: 575-585. Dans la première expérience, deux cathéters ont été placés dans un des sites sélectionnés (veine cave et veine cave avec 7 cm entre les extrémités des cathéters, VC/VC, n = 5; ventricule et oreillette droits, RV/RA, n = 5; aorte antérieure et ventricule gauche, AA/LV, n = 4) pour vérifier l'effet du site de perfusion et de prélèvement sur les cinétiques du CO 2 et de la leucine. Les porcs ont été perfusés i.v. durant 6 h avec du NaH 13 CO 3 (1,45 µmol h -1 kg -1 , précédé d'une dose d'amorçage de 2,05 µmol kg -1 ) et avec de la L-[1-13 C] leucine (9,7 µmol h -1 kg -1 , précédé d'une dose d'amorçage de 9,7 µmol kg -1 ), le lendemain. Aucun effet (P > 0,10) des sites n'a été observé sur l...

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Section: Nah 13 Co 3 Kineticscontrasting

confidence: 53%

Section: Nah 13 Co 3 Kineticsmentioning

confidence: 99%

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Whole-body protein synthesis in growing barrows: diurnal and day-to-day variation and the effect of site of tracer infusion and sampling

Roy¹,

Lapierre²,

Estrada³

et al. 1998

Can. J. Anim. Sci.

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“…During this time heme formation continues until a critical hemoglobin concentration is reached, approximately 30 to 36% of red cell volume (16). Furthermore, there is evidence for a circadian rhythm in protein turnover, with particular reference to bone marrow and glycine metabolism (18,19). Therefore, it was not entirely surprising that we calculated increasing values for fSynHb over the study period (Table 1).…”

Section: Discussionmentioning

confidence: 99%

Measurement of Hemoglobin Synthesis Rate in Vivo Using a Stable Isotope Method

Hibbert

Sutherland

Wright

et al. 2001

Analytical Biochemistry

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We developed a method to measure hemoglobin synthesis rate (SynHb) in humans, assuming that free glycine in the red blood cell (RBC) represents free glycine in bone marrow for hemoglobin synthesis. The present rat study examines this assumption of the method and quantifies SynHb in rats. Sprague-Dawley rats (n = 9) were studied, [2-13 C]glycine was intravenously infused over 24 h (2.5 mg kg −1 h −1 ), blood was drawn for glycine and heme isolation, and bone marrow was harvested for glycine isolation. Isotopic enrichments of glycine and heme were measured, fractional hemoglobin synthesis rate (fSynHb% day −1 ) was calculated, and from this a value for SynHb (mg g −1 day −1 ) was derived. Mean body weight was 446 ± 10 g (mean ± SE) and hemoglobin concentration was 14 ± 0.5 g dl −1 . At 24 h, the mean isotopic enrichment, atom percentage excess (APE), of the RBC free glycine (1.56 ± 0.18 APE) was similar to the bone marrow (1.68 ± 0.15 APE). The rate of incorporation of 13 C into heme increased over time from 0.0004 APE/h between 6 and 12 h, to 0.0014 APE/h between 12 and 18 h, and 0.0024 APE/h between 18 and 24 h. Consequently, fSynHb (1.19 ± 0.32, 2.92 ± 0.66, and 4.22 ± 0.56% day −1 , respectively) and SynHb (0.11 ± 0.03, 0.28 ± 0.05, and 0.42 ± 0.05 mg g −1 day −1 , respectively) showed similar patterns over the 24-h study period. We conclude that (1) enrichment of free glycine in the circulating RBC approximates enrichment of bone marrow free glycine for heme formation and (2) this pattern of hemoglobin synthesis rate is reflecting the characteristic release and gradual maturation of reticulocytes in the circulation. Keywords hemoglobin synthesis; anemia; glycine; bone marrow; rats Hemoglobin metabolism is likely to be adversely affected in nutritional anemias and blood diseases of genetic or nongenetic origin. Many attempts have been made to obtain basic information about blood diseases by estimating the life span of the red blood cell (RBC

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“…This may be determined in part by food intake, but equally appears to be an intrinsic feature of metabolism, which is of fundamental importance for enabling the achievement of homeostasis and metabolic balance. These rhythms are well described but poorly understood as illustrated by the timing and pattern of protein degradation [19,20] . The diurnal pattern appears important for the endogenous synthesis of amino acids and fatty acids with major interaction with the functional activity of the microbiome [21][22][23] .…”

Section: Maintaining Homeostasis: Achieving Balancementioning

confidence: 99%

Nutrition and Liver Health

Jackson

2017

Dig Dis

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Good clinical practice is based on a secure and accurate diagnosis. Poor nutrition is frequently associated with disorders of the liver, and a specific nutrition diagnosis is needed for providing best care and experiencing successful outcome. There is opportunity for better-structured approaches to making secure and consistent nutritional diagnoses in patients with liver disease. Nutrition is the set of integrated processes by which cells, tissues, organs and the whole body acquire the energy and nutrients to retain normal structure and perform the required functions. At the level of the whole body, this is achieved through dietary supply and the capacity of the body to transform the substrates and cofactors necessary for metabolism. All of these domains (diet, metabolic capacity, activity of the microbiome, body composition and the level of demand for energy and nutrients) are influenced by levels of physical activity and can vary according to physiological and pathological disease states. The liver plays a central role in establishing and maintaining these regulated processes. Its capacity to achieve and maintain these functional capabilities is established during one's early life. When these capabilities are exceeded and the ability to maintain the milieu interieur is compromised, ill-health supervenes. Stress tests that assess flow through gateway pathways can be used to determine the maximal capacity and functional reserve for critical functions. The inability of the liver to reliably integrate body lipid metabolism and the accumulation of abnormal lipid are obvious manifestations of impaired regulation both in situations of weight loss, for example, the fatty liver of severe malnutrition, and in situations of energy excess, as in non-alcoholic fatty liver disease. The use of stable isotopic probes and the more recent definition of the variability in the metabolome in different nutritional and pathological states indicate the great potential for clinical tools that would enable a more precise nutritional diagnosis, but these require systematic investigation and application. For the present, approaches that place emphasis on being able to control the metabolic state without exposing the liver to unnecessary metabolic stress remain the basis for successful nutritional support.

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Enrichment in Urinary Ammonia and Urea with Hourly Oral Doses of [15N]glycine: Evidence for a Step Function and a Circadian Rhythm in Protein Turnover

Cited by 7 publications

References 16 publications

Whole-body protein synthesis in growing barrows: diurnal and day-to-day variation and the effect of site of tracer infusion and sampling

Whole-body protein synthesis in growing barrows: diurnal and day-to-day variation and the effect of site of tracer infusion and sampling

Measurement of Hemoglobin Synthesis Rate in Vivo Using a Stable Isotope Method

Nutrition and Liver Health

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