Acute effects of epidermal growth factor on Na+, K+-ATPase-dependent oxygen consumption and the amount of the enzyme units in enterocytes isolated from the jejunum of chickens
1998
Park, H. | McBride, B.W. | Milligan, L.P. | Trouten-Radford, L.M.
Enterocytes from jejunum of male White Leghorn chickens aged 14 d and 20 wk were used to investigate the short-term effect of epidermal growth factor (EGF) on total O2 uptake (TO2) and Na+, K+-dependent O2 uptake (OSO2) and intracellular pH (pHi). Total O2 uptake and OSO2 was decreased (P < 0.05) in enterocytes, isolated from both young and adult birds as concentration of EGF increased in the incubation medium from 0 to 100 ng mL-1. The energy required to support Na+, K+-ATPase activity in jejunal enterocytes obtained from 2-wk-old and 20-wk-old birds was 33-37% and 31-34% of total O2 uptake, respectively. No changes were observed in the amount of the maximal binding sites for 3H-ouabain in enterocytes incubated with EGF; the regulation had not caused rapid decrease in the amount of Na+, K+-ATPase units in the basolateral membrane of enterocytes. Epidermal growth factor caused short-term reduction of pHi as did amiloride. Seemingly, an acute action of EGF in chicken enterocytes in vitro is to reduce the activity of a fixed number of Na+, K+-ATPase units in enterocytes by decreasing Na+, H+-antiport-dependent Na+ influx.
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