title: Reno-submandibular axis controls release of extrarenal inactive renin.
abstract: The mechanisms causing the release of plasma inactive renin (PIR) area still unclear. We have investigated the role of the kidney in the release of trypsin-activable PIR from extrarenal sources in the rat, with special reference to the submandibular gland. The activation of PIR was performed by incubation with 20 mg/ml trypsin at 4 degrees C for up to 10 min; the reaction was then terminated by addition of 20 mg/ml of soybean trypsin inhibitor. Bilateral nephrectomy resulted in a gradual, marked, sex-independent increase in PIR concentration, reaching levels 4.5 times higher than basal in 24 h (time 0: 14.8 +/- 1.0 ng/ml per h; 24 h: 66.8 +/- 3.4 ng/ml per h, mean +/- s.d., P less than 0.001). This increase was not altered by the concomitant intravenous infusion of pressor doses of either angiotensin (Ang) II (30 ng/min) or pure mouse submandibular renin (a 20-ng intravenous bolus followed by intravenous infusion at the rate of 50 ng/h) for 4 h, but was completely prevented by prior removal of the submandibular glands, in which no activity of active renin and no inactive renin was detected. These results suggest that the post-nephrectomy increase of PIR is not dependent on feedback mechanisms of the suppressed renin-angiotensin system, but is controlled by the presence of submandibular glands in the rat.
authors.affiliation: Third Department of Internal Medicine, Gifu University School of Medicine, Tsukasa-machi, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Miyazaki
authors.forename: A
authors.initials: A
authors.lastname: Sakanaka
authors.forename: K
authors.initials: K
authors.lastname: Chimori
authors.forename: J
authors.initials: J
authors.lastname: Kosaka
authors.forename: R
authors.initials: R
authors.lastname: Goi
authors.forename: S
authors.initials: S
authors.lastname: Dodo
authors.forename: K
authors.initials: K
authors.lastname: Miura
authors.forename: F
authors.initials: F
authors.lastname: Suzuki
mesh_terms: D000818:Animals; D004789:Enzyme Activation / Q000187:drug effects; D004792:Enzyme Precursors / Q000097:blood / Q000378:metabolism*; D005260:Female; D007668:Kidney / Q000502:physiology*; D008297:Male; D008970:Molecular Weight; D009392:Nephrectomy; D051381:Rats; D011919:Rats, Inbred Strains; D012083:Renin / Q000097:blood / Q000378:metabolism*; D013363:Submandibular Gland / Q000502:physiology*; D014357:Trypsin / Q000494:pharmacology
chemical_list: D004792:Enzyme Precursors; D014357:Trypsin; D012083:Renin