The Present study was undertaken in order to study the effects of intravenously administered bovine bile and several bile acids on blood pressure in cats. Depressor activity of Sigma bovine bile (Sigma Chemical Co. product) was compared with that of dried bile and depressor activity was compared between cholic acid, glycocholate, taurocholate and deoxycholic acid. Also studied were effects of atropine, propranolol and regitine pretreatment on the depressor responses elicited by intravenously ad-ministered bovine bile and bile acids.
The results obtained are as follows;
1. After intravenous administration of Sigma bovine bile, depressor responses were observed invariably. Sigma bovine bile at doses of 10mg/kg and 20mg/kg elicited 55.4 ± 3.OmmHg and 96.0 ± 4.4mmHg depressor responses, respectively.
2. The maximum depressor responses to 20mg/kg and 30mg/kg of intravenously ad-ministered dried bovine bile were respectively .67.7 ± 5.4mmHg and 85.3 ± 3.9mmHg. And it was recognized that depressor activity of Sigma bovine bile was greater than that of dried bile.
3. From the results of present study it was suggested that generally depressor ac-tivity of bovine bile is greater than that of porcine bile.
4. No changes in depressor responses to Sigma bovine bile were observed in animals pretreated with propranolol while lowered blood pressure was partially blocked by the treatment of animals with either atropine or regitine.
5. Following intravenous administeration of trihydroxy bile acids (30mg/kg), mean arterial blood pressure was decreased approximaely by 40 - 50mmHg. The depressor activity of bile acids were in the order, taurocholate > glycocholate > cholic acid. Depressor responses to DCA were found to be greater than cholates suggesting that dihydroxy bile acid is more effective than trihydroxy bile acid in the elicitation of hypotension.
6. Depressor responses to DCA and glycocholate were partially reduced by pretreat-ment of animal with regitine, while that to taurocholate was partially blocked by atropine as well. No changes in depressor responses to cholic acid was noticed following treatment of animals with above autonomic nerve blockers.
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