Comparative hyperfibrinogenæmic Action of D- and L-Adrenaline

Abstract

IN a previous work on the hyperfibrinogenæmic effect of several sympathomimetic amines, it was reported¹ that adrenaline, when injected subcutaneously into the rat, has the highest activity in increasing blood plasma fibrinogen. We have now compared the activity of D- and L-adrenaline in relation to the hyperfibrinogenæmic response. After a preliminary experiment to find roughly the relative hyperfibrinogenæmic effect of the two forms of adrenaline, the following experiment was carried out. Forty female albino rats of 150–200 gm. body-weight were divided by randomization into four groups of ten rats each. Two groups received subcutaneously respectively 0.03 and 0.06 mgm. of adrenaline (expressed as base)/100 gm. body-weight. The other two groups were injected respectively with 1 and 2 mgm. of D-adrenaline (base). 24 hr. later, the rats were bled from the aorta under pentobarbitone-sodium anæsthesia (4 mgm./100 gm. body-weight) using syringes coated with ‘Dry Film 9987’, clotting being prevented by the addition of 0.01 ml. of 30 per cent potassium oxalate per ml. of blood; the D- and L-adrenaline were Winthrop Research Products. The fibrinogen was determined by the classical technique of Cullen and Van Slyke, with ashing by the method of Campbell and Hanna², distillation and titration of ammonia. The results are summarized in Table 1. The relative potency of D-adrenaline as compared to L-adrenaline was calculated by standard statistical methods for a four-point assay. Our results indicate that the dextro-compound has 2.8 per cent of the activity of the lævo-compound, with the exact fiducial limits of 1.8 and 5.9 per cent. This potency ratio of 1 : 36, obtained for the hyperfibrinogenæmic effect of the dextro-compound in relation to the lævo-compound, is lower than the ratio 1 : 20 obtained by Tainter³ for the pressor response in the cat. It is, however, comparable to the 1 : 30 to 1 : 40 ratio found by Fromherz⁴ for the pressor response in dogs.