AJP - Regulatory, Integrative and Comparative Physiology, Vol 258, Issue 1 99-103, Copyright © 1990 by American Physiological Society
AVP and dDAVP in rabbit cortical collecting tubule: a comparative time-course study
M. Leite Jr and W. N. Suki
Department of Medicine, Baylor College of Medicine, Houston, Texas.
The V2-selective analogue of arginine vasopressin (AVP), dDAVP, has been
used to distinguish between the effects of V1- and V2-receptor activation
by AVP in different cell types of the kidney. Based on studies showing
different effects of AVP and dDAVP on prostaglandin secretion, and also on
cytosolic Ca2+, we designed a comparative time-course study of both
agonists on rabbit microdissected cortical collecting tubules (CCT)
microperfused in vitro at 38 degrees C. Plots of the effects of AVP (10
microU/ml or 2.2 x 10(-11) M and 100 microU/ml or 2.2 x 10(-10) M) and
dDAVP (10 microU/ml or 0.8 x 10(-11) M) on osmotic water permeability (Pf)
at comparable antidiuretic activities, revealed an increase of Pf that was
maintained for as long as 170 min of hormone exposure. Also the magnitude
of increase in Pf and the time required to achieve the more sustained phase
of response were comparable, with no significant difference between the two
agonists. These results clearly demonstrate a stable response of rabbit CCT
to AVP and dDAVP at physiological temperature, and they reveal no evidence
for a difference between the native hormone AVP and its V2 selective
analogue on the net hydrosmotic response of the CCT.
