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31 P NMR study of insulin effects on the isolated perfused rabbit urinary bladder
Author(s) -
Fisher M. J.,
Dillon P. F.
Publication year - 1989
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.1910090108
Subject(s) - rabbit (cipher) , urinary system , urinary bladder , chemistry , insulin , nuclear magnetic resonance spectroscopy , nuclear magnetic resonance , endocrinology , medicine , physics , stereochemistry , mathematics , statistics
Abstract Insulin stimulates hexose transport, intermediary metabolism, and cell growth and development. These effects are well‐documented in skeletal but not smooth muscle. 31 P NMR spectroscopy was performed on rabbit urinary bladders ( n =4) to characterize insulin's actions on smooth muscle. The bladder and its vasculature were surgically isolated from the animal and perfused with a PSS/red blood cell perfusate. After a control steady state was achieved (approx 1−2 h), insulin (0.100 mU/ml) was added to the perfusate. Relative levels of intracellular phosphorylated compounds, pH, and free Mg 2+ were measured and compared to control values. Also, extracellular pH and fractional volume were assessed using phenylphosphonate, a 31 P NMR extracellular pH and volume indicator. Insulin induced significant increases in PCr (16 ± 9%) at the expense of P i , intracellular pH ( Δ 0.24 + 0.07 ), and fractional extracellular volume (49 ± 1%). Intracellular free Mg 2+ and extracellular pH did not change. These results indicate that in situ smooth muscle is sensitive to physiological levels of insulin. In fact, insulin improves the energy state of smooth muscle cells and the overall tissue perfusion. © 1989 Academic Press, Inc.