Intracellular pH of brown adipose tissue increases during norepinephrine stimulation of thermogenesis
Norepinephrine (NE) activation of brown fat (BAT) thermogenesis appears to involve dissociation of purine nucleotides from the mitochondrial uncoupling protein, resulting in release of normal respiratory control and enhanced substrate oxidation. Since the affinity of the uncoupling protein for purine nucleotides decreases significantly with increasing pH, the authors wished to determine if NE administration shifted the intracellular pH of BAT. To examine this question under in vivo conditions, they positioned a nuclear magnetic resonance (NMR) surface coil over the interscapular BAT of anesthetized male Syrian hamsters. The underlying and surrounding musculature was shielded to minimize their contribution to the /sup 31/P spectra. The hamster was placed in a Nicolet 200 Mhz spectrometer, operating in the Fourier Transform mode and tuned to /sup 31/P. Scans taken during infusion of ascorbate buffer (vehicle for NE) were compared to those taken during NE infusion (8 ng/g x min). During this infusion, BAT temperature increased 3.7 +/- 0.5/sup 0/C, confirming that BAT thermogenesis was activated. There also occurred a statistically significant PPM (parts per million) shift, averaging 0.070 +/- 0.022 (n = 22) and corresponding to an increase of approximately 0.07 pH units. This shift in intracellular pH from 7.32 to 7.39, although small, would facilitate the maintenance of loosely coupled brown fat mitochondria.
- Research Organization:
- Univ. of California, Davis
- OSTI ID:
- 5391677
- Report Number(s):
- CONF-8604222-; TRN: 86-028449
- Journal Information:
- Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 45:3; Conference: 70. annual meeting of the Federation of American Society for Experimental Biology, St. Louis, MO, USA, 13 Apr 1986
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
ADIPOSE TISSUE
TEMPERATURE EFFECTS
NORADRENALINE
BIOCHEMICAL REACTION KINETICS
AFFINITY
HAMSTERS
IN VIVO
MITOCHONDRIA
NUCLEAR MAGNETIC RESONANCE
PH VALUE
PHOSPHORUS 31
PURINES
RESPIRATION
ADRENAL HORMONES
ANIMAL TISSUES
ANIMALS
AROMATICS
AUTONOMIC NERVOUS SYSTEM AGENTS
AZAARENES
BODY
CARDIOTONICS
CARDIOVASCULAR AGENTS
CELL CONSTITUENTS
CONNECTIVE TISSUE
DRUGS
HETEROCYCLIC COMPOUNDS
HORMONES
ISOTOPES
KINETICS
LIGHT NUCLEI
MAGNETIC RESONANCE
MAMMALS
NEUROREGULATORS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANOIDS
PHOSPHORUS ISOTOPES
REACTION KINETICS
RESONANCE
RODENTS
STABLE ISOTOPES
STEROID HORMONES
SYMPATHOMIMETICS
TISSUES
VERTEBRATES
550600* - Medicine
550201 - Biochemistry- Tracer Techniques