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Summary. The sera of 30 patients who had been treated with conventional beef insulin were tested for binding of insulin and other pancreatic hormones. All showed antibody binding of insulin, 29 binding of proinsulin, 29 binding of pancreatic polypeptide, two binding of glucagon but none of the sera bound vasoactive intestinal peptide or somatostatin. After changing therapy to highly purified pork insulin the binding capacity of sera for insulin and the other hormones was monitored for up to 35 months and a steady fall was found in nearly all cases. In eight of the patients conventional beef insulin treatment was resumed: in one month binding of insulin and of the other hormones increased back to the initial levels. In eighteen subjects who had only received highly purified pork insulin low levels of insulin binding were found with no binding of proinsulin or other hormones. The amounts of proinsulin and contaminating hormones in highly purified pork insulin are so low that they are not immunogenic; conventional beef insulin not only contains immunogenic amounts of proinsulin and the contaminating hormones pancreatic polypeptide and glucagon but also is more immunogenic than purified pork insulin.Key words: Insulin, proinsulin, pancreatic polypeptide, glucagon, antibodies.Conventional beef insulin preparations are more immunogenic than highly purified pork insulin [1]. They contain appreciable quantities of proinsulin, pancreatic polypeptide (PP), glucagon, somatostatin and vasoactive intestinal peptide (VIP) [2]. The greater immunogenicity of the conventional beef insulins has been attributed to the contaminants although other factors such as alteration or polymerisation of the insulin may be more important. A change of therapy from beef to purified pork insulin involves both a change in the species of insulin origin and an increase in purity as well as a possible change in the physical or chemical state of the insulin.In the present study the antibodies to insulin, proinsulin, PP, glucagon, somatostatin and VIP have been measured in patients treated with conventional beef insulin before and at intervals after a change to highly purified pork insulin. Materials and Methods PatientsThirty insulin treated patients were studied; 17 males and 13 females with an average age at the start of the study of 33 years (range 12-67) and an average duration of diabetes of 12 years (range 5-38).For at least six months before the start of this study all the patients were treated with twice daily soluble and isophane beef insulin with an average daily dose of 55 U (range 24-84): before this some had received other beef insulin preparations including beef/pork mixtures. None of the patients were regarded as "britfie" or insulin resistant, their antibody status was not known when they entered this study and none were taking immunosuppressive drugs or steroids.An initial blood sample was collected and then, after changeover to highly purified pork insulin (twice daily Leo Neutral | and Leo Retard | insulins), blood samples were col...

A microparticulate form of free testosterone was given orally to 6 hypogonadal men. Plasma levels were followed after a 200-mg dose, and a double-peak effect was observed. This suggests that particles of different sizes were absorbed at different rates. The clinical and biochemical effects were observed over a 2-month period, on a dose of 200 mg twice daily, taken in place of the usual androgen replacement. The results indicate that absorption is not sufficiently reliable for routine use. The large doses required to achieve therapeutic levels, make oral administration of free testosterone impractical.