caa a22 4500 465826393 CHVBK 20180323112150.0 cr unu---uuuuu 170327e19900401xx s 000 0 eng 10.1007/BF00258758 doi (NATIONALLICENCE)springer-10.1007/BF00258758 Potassium transport across the intestines of the fowl Gallus domesticus [Elektronische Daten] [Barbara Grubb, P. Bentley] Summary: 1. We investigated potassium (K) transport in vitro across four major segments of the avian intestine. In normal fed birds, the most proximal segment, the duodenum, had very low unidirectional rates of K transport (Jms 6.7 nEq·cm−2·hr−1; Jsm 7.7 nEq·cm−2·hr−1). The jejunum had the greatest unidirectional K flux of the segments studied (Jms 36.6 and Jsm 85.5 nEq·cm−2·hr−1), and this segment showed a net K secretion (48.9 nEq·cm−2·hr−1). The ileum had a significantly lower Jms (16.5 nEq·cm−2·hr−1) than did the jejunum, and this segment also showed a net K secretion (28 nEq·cm−2·hr−1). Potassium transport across the mucosal surface of the colon was very low (Jms 7.7 nEq·cm−2·hr−1) while the Jsm flux was relatively large, giving a net K secretion of 45.7 nEq·cm−2·hr−1. 2. When tissues were bathed in solutions having approximately normal in vivo K concentrations on both sides of the membranes and open circuit PD (to simulate in vivo conditions), the jejunum was the only segment that showed a net K absorption (83 nEq·cm−2·hr−1). 3. When birds were fed a low K diet for 2 weeks, the colon showed the greatest response with Jms for K increasing 12 fold over control. 4. From these studies we conclude that in normal birds the duodenum appears to be relatively impermeable to K and does not appear to play a significant role in K transport. However, the jejunum by virtue of its relatively greater permeability to K, the total length of jejunum comprising the intestine (66%), and the in vivo K gradients, seems to be most important in K absorption in the normal bird. The ileum and colon were major sites of K secretion in vitro and appear to be most important in intestinal regulation of K transport in response to changes in the dietary K load. Springer-Verlag, 1990 In vitro nationallicence Duodenum nationallicence Jejunum nationallicence Ileum nationallicence Codon nationallicence 42K nationallicence 86Rb nationallicence Grubb Barbara Department of Anatomy, Physiological Sciences and Radiology, North Carolina State University, College of Veterinary Medicine, 4700 Hillsborough Street, 27606, Raleigh, NC, USA aut Bentley P. Department of Anatomy, Physiological Sciences and Radiology, North Carolina State University, College of Veterinary Medicine, 4700 Hillsborough Street, 27606, Raleigh, NC, USA aut Journal of Comparative Physiology B Springer-Verlag 160/1(1990-04-01), 17-22 0174-1578 160:1<17 1990 160 360 https://doi.org/10.1007/BF00258758 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00258758 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Grubb Barbara Department of Anatomy, Physiological Sciences and Radiology, North Carolina State University, College of Veterinary Medicine, 4700 Hillsborough Street, 27606, Raleigh, NC, USA aut NATIONALLICENCE 700 1- Bentley P. Department of Anatomy, Physiological Sciences and Radiology, North Carolina State University, College of Veterinary Medicine, 4700 Hillsborough Street, 27606, Raleigh, NC, USA aut NATIONALLICENCE 773 0- Journal of Comparative Physiology B Springer-Verlag 160/1(1990-04-01), 17-22 0174-1578 160:1<17 1990 160 360 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer