Full Papers

Antihypertensive effect of biotin in stroke-prone spontaneously hypertensive rats

Mari Watanabe-Kamiyama^a1, Shin Kamiyama^a1a2, Kimiko Horiuchi^a1, Kousaku Ohinata^a1a3, Hitoshi Shirakawa^a1, Yuji Furukawa^a1 and Michio Komai^a1 c1

^a1 Laboratory of Nutrition, Department of Science of Food Function and Health, Graduate School of Agricultural Science, Tohoku University, 1-1 Tsutsumidori-Amamiyamachi, Aoba-ku, Sendai 981-8555, Japan

^a2 Laboratory of Cell Biology, Department of Bioinformatics, Soka University, Tokyo, Japan

^a3 Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan

Abstract

Biotin is a member of the vitamin B-complex family. Biotin deficiency has been associated with hyperglycaemia and insulin resistance in animals and humans. In the present study, we investigated the pharmacological effects of biotin on hypertension in the stroke-prone spontaneously hypertensive rat (SHRSP) strain. We observed that long-term administration of biotin decreased systolic blood pressure in the SHRSP strain; also, a single dose of biotin immediately decreased systolic blood pressure in this strain. Pretreatment with the guanylate cyclase inhibitor 1H-[1,2,4]oxadiazole [4,3-α]quinoxalin-1-one abolished the hypotensive action of biotin in the SHRSP strain, while pretreatment with the NO synthase inhibitor N^G-nitro-l-arginine methyl ester had no effect on the action of biotin. Biotin reduced coronary arterial thickening and the incidence of stroke in the SHRSP strain. These results suggest that the pharmacological dose of biotin decreased the blood pressure of the SHRSP via an NO-independent direct activation of soluble guanylate cyclase. Our findings reveal the beneficial effects of biotin on hypertension and the incidence of stroke.

(Received March 08 2007)

(Revised June 12 2007)

(Accepted August 23 2007)

Key Words:

• Biotin;
• Hypertension;
• Stroke;
• Soluble guanylate cyclase

Correspondence:

^c1 Corresponding author: Dr Michio Komai, fax +81 22 717 8813, email mkomai@biochem.tohoku.ac.jp

Footnotes

Abbreviations: DW, distilled water; l-NAME, N^G-nitro-l-arginine methyl ester; ODQ, 1H-[1,2,4]oxadiazole [4,3-α]quinoxalin-1-one; SBP, systolic blood pressure; sGC, soluble guanylate cyclase; SHR, spontaneously hypertensive rat; SHRSP, stroke-prone spontaneously hypertensive rat; Wistar, Wistar/Slc; WKY, Wistar–Kyoto