sup 13 C NMR relaxation times of hepatic glycogen in vitro and in vivo

Journal Article · Tue Jul 24 00:00:00 EDT 1990 · Biochemistry; (USA)

DOI:https://doi.org/10.1021/bi00481a009· OSTI ID:5986992

Zang, Lihsin; Laughlin, M R; Rothman, D L; Shulman, R G ^[1]

---

1. Yale Univ., New Haven, CT (USA)

The field dependence of relaxation times of the C-1 carbon of glycogen was studied in vitro by natural-abundance {sup 13}C NMR. T{sub 1} is strongly field dependent, while T{sub 2} does not change significantly with magnetic field. T{sub 1} and T{sub 2} were also measured for rat hepatic glycogen enriched with (1-{sup 13}C)glucose in vivo at 4.7 T, and similar relaxation times were observed as those obtained in vitro at the same field. The in vitro values of T{sub 1} were 65 {plus minus} 5 ms at 2.1 T, 142 {plus minus} 10 ms at 4.7 T, and 300 {plus minus} 10 ms at 8.4 T, while T{sub 2} values were 6.7 {plus minus} 1 ms at 2.1 T, 9.4 {plus minus} 1 ms at 4.7 T, and 9.5 {plus minus} 1 ms at 8.4 T. Calculations based on the rigid-rotor nearest-neighbor model give qualitatively good agreement with the T{sub 1} field dependence with a best-fit correlation time of 6.4 {times} 10{sup {minus}9} s, which is significantly smaller than {tau}{sub M}, the estimated overall correlation time for the glycogen molecule (ca. 10{sup {minus}5} s). A more accurate fit of T{sub 1} data using a modified Lipari and Szabo approach indicates that internal fast motions dominate the T{sub 1} relaxation in glycogen. On the other hand, the T{sub 2} relaxation is dominated by the overall correlation time {tau}{sub M} while the internal motions are almost but not completely unrestricted.

• OSTI ID: 5986992
• Journal Information: Biochemistry; (USA), Vol. 29:29; ISSN 0006-2960
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
GLYCOGEN
NUCLEAR MAGNETIC RESONANCE
CARBON 13
GLUCOSE
IN VITRO
IN VIVO
LIVER
RABBITS
RELAXATION TIME
ALDEHYDES
ANIMALS
BODY
CARBOHYDRATES
CARBON ISOTOPES
DIGESTIVE SYSTEM
EVEN-ODD NUCLEI
GLANDS
HEXOSES
ISOTOPES
LIGHT NUCLEI
MAGNETIC RESONANCE
MAMMALS
MONOSACCHARIDES
NUCLEI
ORGANIC COMPOUNDS
ORGANS
POLYSACCHARIDES
RESONANCE
SACCHARIDES
STABLE ISOTOPES
VERTEBRATES
550601* - Medicine- Unsealed Radionuclides in Diagnostics