Developmental toxicity of ethanol in Drosophila melanogaster

Ethanol was tested for teratogenicity in Drosophila melanogaster. Treatment consisted of rearing the fly larvae in media containing initial ethanol concentrations of 0%, 4%, 8%, or 14% by weight. Emerging flies were inspected for gross malformations. A low frequency of malformations was seen among controls (0.82%), increasing to 10.36% of emerging adults at the highest ethanol dose. The most common malformation involved the legs (segments missing or distorted or complete absence) and wings (uninflated, distorted, or absent). Less frequent defects included fused or missing mouth parts and missing halteres. Also, by exposing staged larvae to ethanol and examining the emerging flies, developmental stage sensitivity of Drosophila was investigated in terms of timing of treatment initiation. The results suggested that the incidence of defects increased with length of exposure. These results support the assumption that ethanol itself is the causative agent in ethanol-induced developmental toxicity and further support the use of Drosophila for developmental toxicity screening.     

A radioreceptor assay for pharmaceutical preparations of insulin

A radioreceptor assay has been developed that is suitable for the measurement of the potency of crystalline insulin and pharmaceutical insulin formulations. It utilizes the well characterized and widely available IM-9 human lymphocyte cell line as the source of receptor. Bovine, porcine and human crystalline and formulated insulins have been assayed against the 4th International and European Standards for Insulin and the potencies compared with those obtained by the mouse blood glucose method. Results with bovine insulin were in full correspondence with the in vivo results. Porcine and human insulins were 15-20% more potent by the radioreceptor assay than by the in vivo method when the mixed bovine and porcine insulin 4th International and European Standards were used, but were equivalent when compared with like materials. Average 95% confidence limits for formulated insulins in two assays were +/- 6% of the mean. The coefficient of variation on repeated assay of the same sample was 3.8%. The three dose parallel line radioreceptor assay with appropriate species species standards is a candidate biological test capable of international adoption as an alternative to in vivo animal testing of insulin.