Inter-relationships between the absorptions of hydrocortisone,sodium, water and actively transported organic solutes in the human jejunum

Summary The effect of intraluminal hydrocortisone (100 mg/l) on sodium and water transport in the small intestine was investigated by jejunal perfusion (flow rate 15 ml/min) of healthy subjects with normal saline and saline containing 56 mmol/l galactose or alanine. Minimal absorption of sodium and water occurred with normal saline and did not change significantly in the presence of hydrocortisone. Galactose and alanine enhanced sodium and water absorption and further significant increases occurred in the presence of hydrocortisone. Glucocorticoidinduced increases in absorption were detected within 20–30 min, while plasma cortisol concentrations were in the normal range. 43% of the perfused dose of hydrocortisone was absorbed with normal saline (p<0.01). There was a significant positive correlation (p<0.0025) between hydrocortisone and water absorption. Thus, in the presence of actively absorbed organic solutes, hydrocortisone rapidly increased sodium absorption and the concurrent increase in water absorption appears to have facilitated passive absorption of hydrocortisone.