L K Munck1, B G Munck. 1. Bispebjerg Hospital, Department of Internal Medicine P, Copenhagen, Denmark.
Abstract
UNLABELLED: 1. Net potassium secretion (JKnet) by the sodium-depleted hen's colon (low sodium colon) is 0.17 +/- 0.07 mumol/cm2.hr. Amiloride or ouabain eliminates short circuit currents (Isc) of 16-20 mumol/cm2.hr without affecting JKsm. 2. In the NaCl-loaded hen's colon (high sodium colon) stimulating Isc by (a) glucose, (b) amino acids, and inhibiting with (c) ouabain changes JKnet from 0.08 +/- 0.04 to (a) 0.42 +/- 0.07, to (b) 0.60 +/- 0.07 to (c) 0.13 +/- 0.13 mumol/cm2.hr. 3. In both colonic types theophylline increases and bumetanide decreases JKnet by 1 mumol/cm2.hr. 4. CONCLUSION: Apical membranes of sodium-absorbing and chloride-secreting cells of the high sodium colon are potassium permeable. In the low sodium colon sodium-absorbing cells have potassium-impermeable apical membranes.
UNLABELLED: 1. Net potassium secretion (JKnet) by the sodium-depleted hen's colon (low sodium colon) is 0.17 +/- 0.07 mumol/cm2.hr. Amiloride or ouabain eliminates short circuit currents (Isc) of 16-20 mumol/cm2.hr without affecting JKsm. 2. In the NaCl-loaded hen's colon (high sodium colon) stimulating Isc by (a) glucose, (b) amino acids, and inhibiting with (c) ouabain changes JKnet from 0.08 +/- 0.04 to (a) 0.42 +/- 0.07, to (b) 0.60 +/- 0.07 to (c) 0.13 +/- 0.13 mumol/cm2.hr. 3. In both colonic types theophylline increases and bumetanide decreases JKnet by 1 mumol/cm2.hr. 4. CONCLUSION: Apical membranes of sodium-absorbing and chloride-secreting cells of the high sodium colon are potassium permeable. In the low sodium colon sodium-absorbing cells have potassium-impermeable apical membranes.