Hs. Hyun et al., EFFECT OF VASOACTIVE INTESTINAL POLYPEPTIDE (VIP) ON THE NET MOVEMENTOF ELECTROLYTES AND WATER AND GLUCOSE-ABSORPTION IN THE JEJUNAL LOOP OF SHEEP, Journal of veterinary medical science, 57(5), 1995, pp. 865-869
The effect of vasoactive intestinal polypeptide (VIP) on glucose absor
ption and the net movement of electrolytes and water in the jejunum of
sheep was investigated using a Thiry-Vella loop. Intraluminal perfusi
on of glucose solution (10 mM) containing NaCl (149 mM) and PEG (1 mg/
ml) was done at 1 ml/min and the outflow solution was collected every
ten minutes. After a 30 min control period, VIP was infused into the j
ugular vein for 30 min at rates of 10, 30, 100, 100 and 1,000 pmol/kg/
hr. In the control period, water, sodium, chloride and glucose were ab
sorbed, while bicarbonate and potassium were secreted. VIP decreased w
ater absorption at 10 and 30 pmol/kg/hr and converted to secretion at
over 100 pmol/kg/hr in a dose-dependent manner. Sodium flux changed to
secretion only at 1,000 pmol/kg/hr, but chloride flux remained absorp
tive even at the highest dose. Bicarbonate secretion was stimulated do
se-dependently by VIP. Potassium secretion was also increased at all d
oses, though this response was not dose-dependent. The net glucose abs
orption was not altered by VIP at any dose. Our findings indicate that
VIP stimulates the jejunal secretion of water, sodium, potassium and
bicarbonate and that VIP does not inhibit glucose absorption when the
secretion of luminal fluid is accelerated by VIP in the jejunal loop o
f sheep.