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Louis Tobian, Mary Ann Johnson, Susan Hanlon, Kathleen Bartemes, A Glomerular Defect in Prehypertensive Dahl S Rats, Which Limits Their Capacity to Increase GFR, American Journal of Hypertension, Volume 2, Issue 7, July 1989, Pages 557–559, https://doi.org/10.1093/ajh/2.7.557
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Abstract
There is a great need to discover traits that predict future human hypertension. Our previous studies found abnormal glomerular filtration rates (GFRs) in isolated kidneys of Dahl S rats. Such GFR alterations were sought in intact, low NaCl, prehypertensive Dahl S rats. Such Dahl S rats are genetically susceptible to NaCI hypertension but are normotensive on low NaCl. On .3% l ow NaCl, BP of 12 Dahl S rats averaged 138 mm Hg ν 131 in 12 Dahl R rats (NS). Glomerular filtration rates under inactin anesthesia were measured during two 20-minute periods before a 20-minute amino acid infusion and also during three 20-minute periods after the amino acid infusion. Before the amino acid infusion, GFRs averaged 3.3 mL/min in S rats ν 3.25 in R rats (NS). After the amino acid infusion, R rats showed a progressive rise in GFR: 4.7, 5.1 and 5.4 in three successive 20-minute periods. In these same three periods after amino acids, the S rats had GFRs of 3.8, 3.8, and 3.8. Thus R rats had an 81% increase of GFR after amino acids, whereas S rats increased only 18%, a 78% lower increase, P <.001. The R rats had the normal rise of GFR in response to an amino acid load. Prehypertensive S rats had virtually no increase in GFR after the amino acid infusion. Even though both S & R rats had BPs well within the normal range, the ability to increase GFR after amino acid infusion was markedly impaired in prehypertensive S rats. This defect could possibly be used to predict future hypertension. In these S rats, afferent arterioles seem to be almost maximally dilated, such that amino acids can produce no further dilation. This maximum dilation is likely an adaptation to an intrinsic defect in the glomerular filtering membrane of S rats. Am J Hypertens 1989;2:557–559
