Evidence for the AT1 subtype of the angiotensin II receptor in the rat submandibular gland.
We have characterized angiotensin II (Ang II) receptor subtypes on rat submandibular gland membranes using a radioligand binding assay. [3H]Ang II binding to the membrane fractions exhibited both high (Kd =0.08 nm, Bmax =2.19 fmol/mg protein) and low (Kd =4.19 nm, Bmax = 13.7 fmol/mg protein) affinity. Ang 11, Ang III and saralasin completely displaced the [3H]Ang II binding, whereas CV-11974, an AT1 receptor antagonist and PD123319, an AT2 receptor antagonist maximally displaced up to approximately 87 and 13% of the total binding, respectively. [3H]DuP753 binding to the membrane fractions exhibited a single population of binding site with a Kd of 4.22 nM and Bmax of 3.77 pmol/mg protein. Ang II, Ang III and CV-11974 completely displaced the [3H]DuP753 binding with slope factors near unity, but PD123319 did not. These findings suggest that rat submandibular gland membranes contain predominantly the AT1 receptor subtype.
Matsubara
S
S
Department of Physical Education, Nihon University College of Pharmacy, Funabashi, Chiba, Japan.
Saito
K
K
Kizawa
Y
Y
Sano
M
M
Osawa
M
M
Iwamoto
K
K
Murakami
H
H
D057911:Angiotensin Receptor Antagonists; D000818:Animals; D001667:Binding, Competitive / Q000187:drug effects; D066298:In Vitro Techniques; D007700:Kinetics; D008297:Male; D008566:Membranes / Q000378:metabolism; D011869:Radioligand Assay; D051381:Rats; D017208:Rats, Wistar; D044140:Receptor, Angiotensin, Type 1; D044139:Receptor, Angiotensin, Type 2; D011945:Receptors, Angiotensin / Q000819:agonists / Q000378:metabolism*; D013363:Submandibular Gland / Q000378:metabolism*
D057911:Angiotensin Receptor Antagonists; D044140:Receptor, Angiotensin, Type 1; D044139:Receptor, Angiotensin, Type 2; D011945:Receptors, Angiotensin