Comparative effects of growth hormone on water and ion transport in rat jejunum, ileum, and colon

Abstract

Specific growth hormone (GH) receptors are located along the entire rat intestine. We have recently shown that GH induces water and ion absorption in the rat ileum. This raises the possibility that GH regulates water and ion transport throughout the intestine. To test this, we have evaluated the effects of GH administration on jejunal, ileal, and colonic water and ion transport, by the in vivo rat perfused intestine, and in vitro, in corresponding segments of intestine mounted in Ussing chambers. In vivo, GH increased water absorption by 250%, 180%, and 80% over baseline in the jejunum, ileum, and colon, respectively. The effect had similar kinetics in the three intestinal regions. In vitro, serosal GH administration induced a decrease in short-circuit current, consistent with an absorptive effect. The effect showed a proximal to distal decreasing pattern. These findings suggest that GH plays a role in the body fluid homeostatic control, promoting water and ion absorption.

Growth Hormone Stimulates, Through Tyrosine Kinase, Ion Transport and Proliferation in Human Intestinal Cells

“…We have demonstrated that GH directly stimulates both ion absorption and cell growth in human‐derived enterocytes. The GH‐induced decrease in Isc was similar to that observed in a rat model (11,12) and is consistent with an increased flux of an anion from the mucosal to the serosal compartment as a consequence of its increased absorption or decreased secretion. In fact, the abrogation of the Isc response in the Cl ‐ ‐free Ringer's experiment suggests that Cl ‐ transport is involved in the Isc response.…”

“…It increases water and ion absorption in the perfused rat intestine in vivo, and, consistent with an anion‐absorptive effect, it decreases the short‐circuit current in the unstripped rat intestine mounted in an Ussing chamber (11). The absorptive effects are exerted throughout the rat intestine (12), but the intensity of the ion‐absorptive effect decreases in a proximal‐to‐distal direction (12). This region‐specific distribution of absorptive effects resembles the pattern of the trophic effect induced by GH in the intestine (13).…”

Fecal Stream Is Essential for Adaptive Induction of Glucose-Coupled Sodium Transport in the Remnant Ileum After Total Proctocolectomy

“…1,14 The remnant small intestine is an essential organ for ''adaptive'' changes (so-called intestinal adaptation), in particular, altered electrolyte and water absorption. 1,24,25 Water and electrolyte transport in the ileal mucosa are affected by hormones, 26 microcirculation, 27 neural signals and transmitters, 28 and mucosal immune and mesenchymal cells 27 and the humoral factors secreted from them. 13 In the present study, we focused on the function of glucose-coupled sodium transport and SGLT-1 expression levels in intestinal epithelia.…”

Effect of exercise on key pharmacokinetic parameters related to metformin absorption in healthy humans: A pilot study

“…A third explanation could be that intestinal ion fluxes are regulated by several agents, such as growth hormone (GH), which increases basal intestinal water and ion absorption, directly interacting with the enterocyte in in vivo and in vitro animal models. [35][36][37] High-intensity exercise increases serum GH concentration in humans, and this response is not affected by the ingestion of glucose prior to exercise. 38 Thus, an exercise-induced increase in GH could stimulate metformin intestinal absorption through the modulation of cationic transporters in the apical membrane of the enterocyte.…”