Korean Journal of Nephrology 2000;19(1):58-63.

원저 : Oxytocin에 의한 내수질집합관의 cAMP 생성 및 요배설의 변화 (Increases of cAMP Production and Urinary cAMP Excretion by Oxytocin in the Inner Medullary Collecting Duct(IMCD))

한진석(Jin Suk Han),이정상(Jung Sang Lee),김강석(Kang Seock Kim),허우성(Woo Seong Huh),김연수(Yon Su Kim),전은실(Un Sil Jeon),주권욱(Kwon Wook Joo),안규리(Curie Ahn),김성권(Suhnggwon Kim),이중건(Jung Geon Lee),나기영(Ki Young Na),정우경(Woo Kyung Jung)

Abstract

Oxytocin, like vasopressin, has been known to act in the IMCD by the activation of adenylyl cyclase through V2 receptor, but the exact mechanism of its action remains to be elucidated. To prove whether oxytocin is involved in the activation of adenylyl cyclase in the renal collecting duct, we measured the cAMP production and urinary cAMP excretion rate. After single IMCD segments of Sprague-Dawley rats were microdissected and treated with different con- centrations of vasopressin(10pM, 10nM) and oxytocin (10pM, 10nM), cAMP production was measured. Urinary cAMP excretion rate was measured after dehydration and intraperitoneal injection of vasopressin and oxytocin. The results are as follows. 1) cAMP production in single IMCD was significantly increased in vasopressin group(10pM: 48,9±4.7(mean±SE), 10nM:94.6±5.3fmol/mm) and oxy-tocin group(10pM: 11.3±2.9, 10nM: 65.7±6.1fmol/mm) compared with that in the control(3.2±0.2fmol/ mm). 2) Urine volume was significantly decreased in dehydration group(40±7μl/hour) and vasopressin group(420±120μl/hour), but urine volume of oxytocin group(1,480±230μl/hour) was not different from that of control(1,550±120μl/hour). Urine osmolality was significantly increased in all experimental groups(control: 737.0±132.6, dehydration group : 2,463.9± 412.5, vasopressin group : 1,702±412.5, oxytocin group 1,293.4±117.9mOsm/kg). Urinary cAMP excretion rate was significantly increased in dehydration group(4,149.5±1,072.3pmol/hour) and oxytocin group(4,843.3±2,341.8pmol/hour), but not in vasopressin group(1,358.1±690.2pmol/hour), compared with that in control(49±10.7pmoVhour). These results suggest that oxytacin has anti-diuretic effect by the activation of adenylyl cyclase through V2 receptor.