Increases of cAMP Production and Urinary cAMP Excretion by Oxytocin in the Inner Medullary Collecting Duct(IMCD).
- Author:
Ki Young NA
1
;
Un Sil JEON
;
Kwon Wook JOO
;
Woo Seong HUH
;
Jung Geon LEE
;
Woo Kyung JUNG
;
Kang Seock KIM
;
Yon Su KIM
;
Curie AHN
;
Jin Suk HAN
;
Suhng Gwon KIM
;
Jung Sang LEE
Author Information
1. Department of internal medicine, College of Medicine, Seoul National University, Seoul, Korea.
- Publication Type:Original Article
- Keywords:
Oxytocin;
Vasopressin;
cAMP;
ade-nylyl cyclase;
V(2)receptor, IMCD
- MeSH:
Adenylyl Cyclases;
Dehydration;
Injections, Intraperitoneal;
Osmolar Concentration;
Oxytocin*;
Rats, Sprague-Dawley;
Receptors, Vasopressin;
Vasopressins
- From:Korean Journal of Nephrology
2000;19(1):58-63
- CountryRepublic of Korea
- Language:Korean
-
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+/-7Ml/hour) and vasopressin group(420+/-120Ml/hour), but urine volume of oxytocin group(1,480+/-230Ml/hour) was not different from that of control(1,550+/-120Ml/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.
