A bit of googling found this:
the Nobel prize lecture by Banting 1925
Quote:
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The method of estimating the potency of Insulin solutions is based on the effect that Insulin produces upon the blood sugar of normal animals. Rabbits serve as the test animal. They are starved for twenty four hours before the administration of Insulin. Their weight should be approximately 2 kg. Insulin is distributed in strengths of 10, 20, 40 and 80 units per c.c. The unit is one third of the amount of material required to lower the blood sugar of a 2 kg. rabbit which has fasted twenty four hours from the normal level (0.118 percent) to 0.045 percent over a period of five hours. In a moderately severe case of diabetes one unit causes about 2.5 grammes of carbohydrate to be utilized. In earlier and milder cases, as a rule, one unit has a greater effect, accounting for three to five grammes of carbohydrate
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http://www.discoveryofinsulin.com/FGBLecture.htm][/
I found that the rabbit method of assaying insulin was used until recently, when animal insulins were used there could be variations in potency. Today,chromatography is usually used. However the test is still done (at least I found a firm who specialised in this type of testing and the US pharmocopeia gives instructions for the procedure.
A British test used mice
Quote:
To determine the
potency of unmodified insulin the test is to inject two groups of mice, one with insulin of a known strength (standardised by reference to the international standard preparation), the other with the insulin under test. A comparison of the incidence of hypoglycaemic convulsions in the two groups shows the strength of the sample vis-a-vis the standard.
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This report is interesting as it describes how animal insulins were produced
