In an effort to put this information in one place for discussion I have compiled my research across the web for this post. I will be putting links to credits as needed.
I have not tried this, so please use this as information only as a just in case.
One thing all diabetics face in a SHTF scenario is the eventual lack of meds or maybe the inability to get them, while some will be able to cope via herbal remedies, diet and exersize, some heavily insulin dependent diabetics will be looking as a very gruesome ride.
I am a type 1 diabetic diagnosed at 26, mostly weight and inactivity related (was probably type 2 for a bit) I now rely on insulin (lantis) and (humalog) to maintain a good state of health. While exercise and diet have played a large role in reducing my needs, during sickness and stress sometimes uncontrollable things can happen to your blood sugar.
As you can guess once I became more survival minded (5days in the ICU tends to do that) I saw a need to know that it was at least possible to manufacture on some scale insulin.
Here is what I have found out so far.
This is a link to an old story that I first heard on another forum about a person during world war 2 that manufactured and distrubted insulin using 1920's tech to keep alive a great deal of diabetics during the war.
This was my first sign of hope should I ever or anyone ever need to attempt to make it themselves, they were after all in occupied China. Given the lack of quality of the blackmarket insulin at the time and price 1 gold ounce bar would get you a small supply, but one of her friends had died from this which inspired her husband and herself to learn how to make it.
They managed to collect a book, "Beckman's Internal Medicine" described the methods that Dr. Frederick Banting and Charles Best first used to extract insulin from the pancreases of dogs, calves, and cows in 1921.
From here you can guess that after great trouble they began to successfully produce useable insulin for humans that sustained what is rumored to be more than 2-3000 diabetics.
So it can be done, the part of all this that will be dangerous and hard is the testing of the strength of the insulin. Any diabetic can tell you what happens with to much insulin.
I found this information @ http://medtech.syrene.net/forum/showthread.php?t=3442
by using google
At the end of July, Banting operated on one of the duct tied dogs and found that the ligature had held and that the pancreas had shrunk to about one-third of of its normal size. The gland was removed, chopped up and ground in a mortar with saline, strained and a small amount injected into a vein of a depancreatized or diabetic dog. This animal was observed very carefully and with anxiety, for there was great concern that it may have toxic effects as earlier experimenters had discovered. For a while there seemed to be no change, then later to dog showed improvement. The animal became a much more active and more important the blood sugar levels were significantly reduced demonstrating the soundness of Banting's theory.
Although they were jubilant over the result of this experiment, there was some fear that it may have been as spurious result of no real significance. Consequently they injected the substance into other diabetic dogs with the same dramatic result and now felt confident that they had isolated the anti-diabetic factor from the islets of Langerhans in the pancreas. Banting's theory had been proven, but still diabetes had not been conquered even though the groundwork had been laid and there were still problems to overcome. On Dr. MacLeod’s return from Europe he was impressed, but insisted that the whole procedure be repeated to confirm this truly admirable result. The results, of course, with further experiments were confirmed. MacLeod was convinced and the announcement of discovery was presented in papers through the Physiological Journal Club in Toronto on November 14th , and the American Physiological Society shortly before the end of year in 1921. Many publications followed.
In the fall of 1922 the extract was still impure and they were experiencing considerable difficulty with deterioration, sensitization, reaction, etc., although Collip had prepared an extract which could be injected into humans and was a great improvement in the purification of the product. Collip also working with rabbits discovered the dangerous effects of too much insulin producing hypoglycemia and the basis for him believe biological assay of insulin. There were still, however, problems to be overcome come the main one of which production of the product in large enough quantities to be useful clinically. Consequently, the third stage of the development of insulin was being approached and methods were found to extract insulin from the adult beef pancreas, for the supply from the tilt calves was certainly much too small and with further work, without going into details which are contained in Stevenson's book on Sir Frederick Banting, it was possible to produce insulin from the adult beef pancreas.
And from Frederick Banting's Nobel Lecture in 1925:
Best and Scott who are responsible for the preparation of Insulin in the Insulin Division of the Connaught Laboratories have tested all the available methods and have appropriated certain details from many of these, several new procedures have been found advantageous have been introduced by them. The yield of Insulin obtained by Best and Scott at the Connaught Laboratories, by a preliminary extraction with dilute sulphuric acid followed by alcohol is 1,800 to 2,220 units per kg. of pancreas.
The present method of preparation is as follows. The beef or pork pancreas is finely minced in a larger grinder and the minced material is then treated with 5 c.c. of concentrated sulphuric acid, appropriately diluted, per pound of glands. The mixture is stirred for a period of three or four hours and 95% alcohol is added until the concentration of alcohol is 60% to 70%. Two extractions of the glands are made. The solid material is then partially removed by centrifuging the mixture and the solution is further clarified by filtering through paper. The filtrate is practically neutralized with NaOH. The clear filtrate is concentrated in vacuo to about 1/15 of its original volume. The concentrate is then heated to 50oC which results in the separation of lipoid and other materials, which are removed by filtration. Ammonium sulphate (37 grams. per 100 c.c.) is then added to the concentrate and a protein material containing all the Insulin floats to the top of the liquid. The precipitate is skimmed off and dissolved in hot acid alcohol. When the precipitate has completely dissolved, 10 volumes of warm alcohol are added. The solution is then neutralized with NaOH and cooled to room temperature, and kept in a refrigerator at 5oC for two days. At the end of this time the dark coloured supernatant alcohol is decanted off. The alcohol contains practically no potency. The precipitate is dried in vacuo to remove all trace of the alcohol. It is then dissolved in acid water, in which it is readily soluble. The solution is made alkaline with NaOH to PH 7.3 to 7.5. At this alkalinity a dark coloured precipitate settles out, and is immediately centrifuged off. This precipitate is washed once or twice with alkaline water of PH 9.0 and the washings are added to the main liquid. It is important that this process be carried out fairly quickly as Insulin is destroyed in alkaline solution. The acidity is adjusted to PH 5.0 and a white precipitate readily settles out. Tricresol is added to a concentration of 0.3% in order to assist in the isoelectric precipitation and to act as a preservative. After standing one week in the ice chest the supernatant liquid is decanted off and the resultant liquid is removed by centrifuging. The precipitate is then dissolved in a small quantity of acid water. A second isoelectric precipitation is carried out by adjusting the acidity to a PH of approximately 5.0. After standing over night the resultant precipitate is removed by centrifuging. The precipitate, which contains the active principle in a comparatively pure form, is dissolved in acid water and the hydrogen ion concentration adjusted to PH 2.5. The material is carefully tested to determine the potency and is then diluted to the desired strength of 10, 20, 40 or 80 units per c.c. Tricresol is added to secure a concentration of 0.1 percent. Sufficient sodium chloride is added to make the solution isotonic. The Insulin solution is passed through a Mandler filter. After passing through the filter the Insulin is retested carefully to determine its potency. There is practically no loss in berkefelding. The tested Insulin is poured into sterile glass vials with aseptic precautions and the sterility of the final product thoroughly tested by approved methods.
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.
My motivation for posting this was a request in another thread especially since as far as I can tell from searching that it has not been written about on this site as of yet.
I hope that I have properly linked to the sources and I hope this provides some hope for those survivalist diabetics out there.
To be honest though this stuff will be a powerful barter item if anything bad were to happen to our supplies. I try to keep 6 months worth of my stuff on hand, but even stretching that to the max my lantis and humalog (which is synthetic) only lasts a year from manufacturing in the specified temps.
I hope this starts some discussion about the thesability of trying to make your own now. While it is completly possible, it is very serious and a dangerous undertaking.