Effects of AVP and deoxycorticosterone on Na+ and water transport in the Dahl salt-sensitive rat CCD.
Cortical collecting ducts (CCD) from inbred Dahl salt-sensitive rats were perfused in vitro to study effects of arginine vasopressin (AVP, present in the bath) and deoxycorticosterone pivalate (DOC) pretreatment on lumen-to-bath and bath-to-lumen fluxes of 22Na+ (J1----b and Jb----1 in pmol.min-1.mm-1, respectively), hydraulic conductivity (Pf, microns/s), and transepithelial voltage (VT, mV). J1----b was 37.1 +/- 5.3 (mean +/- SE) in untreated rats and increased to 83.2 +/- 15.9 with AVP. VT increased from -0.3 +/- 0.6 to -7.0 +/- 2.0. In DOC-pretreated rat CCDs, baseline J1----b was higher (85.1 +/- 7.6) as was VT (-11.3 +/- 1.7); J1b----b and VT were doubled with AVP addition (185.6 +/- 18.6 and -21.7 +/- 2.3, respectively). Thus J1----b in AVP-stimulated CCDs from untreated rats was not significantly different from control (no AVP) J1----b from DOC-pretreated rats; however, AVP produced a greater J1----b increase in the latter CCDs. Neither AVP nor DOC had an effect on Jb----1, which ranged from 25 to 50. Benzamil reduced J1----b to values not significantly different from Jb----1, and VT became zero in CCDs treated with both AVP and DOC, indicating Na+ transport stimulated by both hormones occurs through apical membrane Na+ channels. Pf increased from 59 +/- 80 to 1,072 +/- 176 with AVP addition to untreated rat CCDs and was unaltered by DOC or benzamil. Thus the Dahl rat CCD exhibits a transport response to AVP and DOC that is indistinguishable from that observed in Sprague-Dawley rats, as previously reported by this laboratory.
Hawk
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Department of Physiology, University of Alabama 35294.
Schafer
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JA
D000042:Absorption; D000584:Amiloride / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D001127:Arginine Vasopressin / Q000494:pharmacology*; D001834:Body Water / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D003900:Desoxycorticosterone / Q000494:pharmacology*; D004357:Drug Synergism; D006973:Hypertension / Q000139:chemically induced*; D007685:Kidney Tubules, Collecting / Q000187:drug effects / Q000378:metabolism*; D007700:Kinetics; D008297:Male; D009994:Osmolar Concentration; D051381:Rats; D011919:Rats, Inbred Strains; D012964:Sodium / Q000378:metabolism*; D015222:Sodium Channels / Q000378:metabolism; D012982:Sodium, Dietary / Q000008:administration & dosage / Q000009:adverse effects*
D015222:Sodium Channels; D012982:Sodium, Dietary; C013407:benzamil; D001127:Arginine Vasopressin; D003900:Desoxycorticosterone; D000584:Amiloride; D012964:Sodium