TY - JOUR
T1 - Prostaglandin E2 regulation of ion transport is absent in medullary thick ascending limbs from SHR
AU - Good, D. W.
AU - Caflisch, C. R.
AU - George, T.
PY - 1995
Y1 - 1995
N2 - Regulation of HCO3/- and Cl- absorption by arginine vasopressin (AVP) and prostaglandin E2 (PGE2) was examined in isolated, perfused medullary thick ascending limbs (MTAL) from 4- to 7-wk-old spontaneously hypertensive (SHR) and Wistar-Kyoto (WKY) rats. AVP inhibited HCO3/- absorption by 50% at 10-10 M and by 25% at 2 x 10-12 M in MTAL from both WKY and SHR. Cholera toxin (10-9 M) or forskolin (10-6 M) in the bath also inhibited HCO3/- absorption by 50% in the SHR. In MTAL from WKY, PGE2 (10-6 M in the bath) increased HCO3/- absorption from 7.1 ± 0.4 to 12.0 ± 0.4 pmol · min-1 · mm-1 (p < 0.005) and decreased Cl- absorption from 65 ± 7 to 47 ± 6 pmol · min-1 · mm-1 (P < 0.001) in the presence of 10-10 M AVP. Under the same conditions, PGE2 had no effect on HCO3/- or Cl- absorption in MTAL from SHR. PGE2 also reversed submaximal inhibition of HCO3/- absorption by 2 x 10-12 MAVP in WKY but not in SHR. With 10- 10 M AVP in the bath, phorbol 12-myristate 13-acetate (10-6 M in the bath) increased HCO3/- absorption from 6.6 ± 0.5 to 12.3 ± 0.4 pmol · min-1 · mm-1 in MTAL from WKY and from 7.6 ± 0.7 to 12.6 ± 1.2 pmol · min-1 · mm-1 in MTAL from SHR (P < 0.005). These results demonstrate that 1) the effects of PGE2 to stimulate HCO3/- absorption and inhibit Cl- absorption in the presence of AVP are absent in MTAL from SHR, 2) the defect may involve an inability of PGE2 to stimulate protein kinase C, and 3) regulation of HCO3/- absorption by AVP via adenosine 3',5'-cyclic monophosphate is similar in MTAL from WKY and SHR. The lack of PGE2 inhibition of NaCl absorption in the MTAL may contribute to renal salt retention during the development of hypertension in the SHR.
AB - Regulation of HCO3/- and Cl- absorption by arginine vasopressin (AVP) and prostaglandin E2 (PGE2) was examined in isolated, perfused medullary thick ascending limbs (MTAL) from 4- to 7-wk-old spontaneously hypertensive (SHR) and Wistar-Kyoto (WKY) rats. AVP inhibited HCO3/- absorption by 50% at 10-10 M and by 25% at 2 x 10-12 M in MTAL from both WKY and SHR. Cholera toxin (10-9 M) or forskolin (10-6 M) in the bath also inhibited HCO3/- absorption by 50% in the SHR. In MTAL from WKY, PGE2 (10-6 M in the bath) increased HCO3/- absorption from 7.1 ± 0.4 to 12.0 ± 0.4 pmol · min-1 · mm-1 (p < 0.005) and decreased Cl- absorption from 65 ± 7 to 47 ± 6 pmol · min-1 · mm-1 (P < 0.001) in the presence of 10-10 M AVP. Under the same conditions, PGE2 had no effect on HCO3/- or Cl- absorption in MTAL from SHR. PGE2 also reversed submaximal inhibition of HCO3/- absorption by 2 x 10-12 MAVP in WKY but not in SHR. With 10- 10 M AVP in the bath, phorbol 12-myristate 13-acetate (10-6 M in the bath) increased HCO3/- absorption from 6.6 ± 0.5 to 12.3 ± 0.4 pmol · min-1 · mm-1 in MTAL from WKY and from 7.6 ± 0.7 to 12.6 ± 1.2 pmol · min-1 · mm-1 in MTAL from SHR (P < 0.005). These results demonstrate that 1) the effects of PGE2 to stimulate HCO3/- absorption and inhibit Cl- absorption in the presence of AVP are absent in MTAL from SHR, 2) the defect may involve an inability of PGE2 to stimulate protein kinase C, and 3) regulation of HCO3/- absorption by AVP via adenosine 3',5'-cyclic monophosphate is similar in MTAL from WKY and SHR. The lack of PGE2 inhibition of NaCl absorption in the MTAL may contribute to renal salt retention during the development of hypertension in the SHR.
KW - adenosine 3',5'-cyclic monophosphate
KW - arginine vasopressin
KW - essential hypertension
KW - loop of Henle
KW - protein kinase C
KW - spontaneously hypertensive rat
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U2 - 10.1152/ajprenal.1995.269.1.f47
DO - 10.1152/ajprenal.1995.269.1.f47
M3 - Article
C2 - 7631831
AN - SCOPUS:0029096597
SN - 0193-1849
VL - 269
SP - F47-F54
JO - American Journal of Physiology - Endocrinology and Metabolism
JF - American Journal of Physiology - Endocrinology and Metabolism
IS - 1 38-1
ER -