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EXPERIMENTAL DISSOCIATION OF THE EFFECTS OF PROSTAGLANDINS ON RENAL SODIUM AND WATER REABSORPTION BY CYCLO‐OXYGENASE INHIBITORS IN THE RAT
Author(s) -
BARTOLI ETTMORE,
BRANCA GIAN FRANCO,
FAEDDA ROSSANA,
OLMEO NINA A.,
SATTA ANDREA,
SOGGIA GIOVANNI
Publication year - 1982
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1982.tb09227.x
Subject(s) - chemistry , reabsorption , endocrinology , free water clearance , medicine , urine osmolality , renal sodium reabsorption , urine flow rate , cyclooxygenase , vasopressin , prostaglandin , excretion , sodium , biochemistry , enzyme , organic chemistry
1 The relative importance of the effect of prostaglandins on renal sodium and water reabsorption was assessed in rats. 2 Clearance experiments were performed on 24 anaesthetized rats divided into 3 groups. Each group was infused throughout either with Ringer solution at 9 ml/h (Protocol I), or at 3 ml/h (Protocol II) or with hypotonic fluid at 5 ml/h (Protocol III). Clearance periods were performed before and after intravenous injection of indomethacin (5 mg/kg) and then of aspirin (20 mg/kg). The natriuretic response to different degrees of volume expansion was not modified during the action of the inhibitors. 3 When baseline urine osmolality (Uosm) was high (Protocol II) no further increase occurred in the presence of prostaglandin inhibition. Conversely, Uosm rose from 771 ± 134 to 1356 ± 414 and from 575 ± 245 to 841 ± 407 mosm/kg ( P < 0.05) in Protocol I and Protocol III respectively, when antidiuretic hormone secretion was inhibited by the higher degree of volume expansion. 4 There was a significant correlation between the change in urine flow rate induced by cyclo‐oxygenase inhibitors and the attendant variations in Na excretion, r = 0.42, n = 41, P < 0.01. 5 Thus, prostaglandins affect Na loss during saline load as a side effect of their action on water permeability. They could play an important role in volume depletion by counterbalancing the large secretion rate of renal vasoconstrictors.