RENAL ADAPTATION TO STRESS - A POSSIBLE ROLE OF ENDOTHELIN RELEASE AND PROSTAGLANDIN MODULATION IN THE HUMAN SUBJECT

The aim of this study was to define the neurohumoral response associat ed with the renal hemodynamic perturbations induced by mental stress a cting as an adrenergic stimulus. In 8 healthy women, the effects of me ntal stress were studied during four consecutive 30-minute periods (ba seline, mental stress, recovery I, recovery II). Mental stress induced sympathetic activation as evidenced by increases in blood pressure, h eart rate, and plasma norepinephrine level. Effective renal plasma flo w (iodine 131-labeled hippurate clearance) decreased only during menta l stress (-22%, p < 0.05 vs baseline); glomerular filtration rate (iod ine 125-labeled iotalamate clearance) remained constant during the ent ire experiment; the filtration fraction increased significantly during mental stress and recovery I (+30% and +22%, respectively, p < 0.02 f or both). Complex neuroendocrine responses were associated with the he modynamic changes. Urinary excretion of endothelin-l and 6-keto-PGF(1 alpha) increased during mental stress (+53%, p < 0.01, and +20%, p < 0 .01, respectively) and recovery I (+49% and +29%, respectively, p < 0. 01 for both). Urinary cyclic guanosine monophosphate rose only during mental stress (+77%, p < 0.05), whereas excretion of PGE, showed a ste pwise increase throughout recovery I and II (+292%, p < 0.01, and +360 %, p < 0.001, respectively). In conclusion, the present experiments de monstrate that renal hemodynamic response induced by mental stress is a complex reaction in which endothelin-1, prostaglandins, and presumab ly nitric oxide take part.