Mechanism for the Antihypertensive Effect of a Polysaccharide-glycopeptide Complex fromLactobacillus caseiin Spontaneously Hypertensive Rats (SHR)

Pharmacological studies on the antihypertensive effect of a polysaccharide-glycopeptide complex (SG-1) isolated from Lactobacillus casei were carried out by using spontaneously hypertensive rats (SHR). An antihypertensive effect of SG-1 was observed by oral, but not by intravenous or intraperitoneal administration, and the effect was attenuated by orally pre-treating with indomethacin. A single oral administration of SG-1 (20 mg/kg) decreased the peripheral vascular resistance (PR). The daily oral administration of SG-1 (10 mg/kg) for 14 days had no effect on either the urine volume or urinary electrolytes (Na+, K+, and Cl-), but it did increase the excretion of 6-keto-PGF1 alpha, a metabolite of PGI2, in the urine. Moreover, a single oral administration of SG-1 (20 mg/kg) also increased the biliary 6-keto-PGF1 alpha excretion. These results suggest that the antihypertensive effect of orally administered SG-1 resulted from an enhancement of PGI2 biosynthesis and the subsequent decrease in PR.