| First Author | Coleman DL | Year | 1978 |
| Journal | Mouse News Lett | Volume | 59 |
| Pages | 25 | Mgi Jnum | J:13772 |
| Mgi Id | MGI:61951 | Citation | Coleman DL, et al. (1978) Tubby (tub). Mouse News Lett 59:25 |
| abstractText | Full text of MNL contribution: New mutants & biochemical variants: 1. Tubby (tub). This new autosomally inherited recessive mutation was found in the C57BL/6J inbred strain in 1977. Tubby mice are recognized by increased body weight which first becomes obvious at 3-4 months in males and 4-6 months in females. Both sexes are fertile. Attained body weight in both sexes of tubby mice is about 60 g by 6 months as compared with 30 g and 25 g for normal males and females, respectively. This increased weight is composed of excess adipose tissue associated with all fat deposits. Because of the phenotypic similarities to diabetes and obese, routine blood sugar and plasma insulin determinations were made monthly on tabby mice. Blood sugar concentrations are in the normal range up to 9 months (oldest mice studied to date). Plasma iimnunoreactive insulin was increased to 2 times normal prior to obvious signs of obesity. Plasma insulin concentrations increase gradually throughout life from 60 to 100 uU/ml at 2 months, to 400 to 1000 uU/per ml at 6 months (normal values, 20-40 uU/ml). The islets of Langerhans are moderately enlarged and show indications of hyperactivity in the later stages. Degranulation of beta cells probably occurs but is not evident by light microscopy. Liver glycogen is slightly increased, whereas total liver lipids range from 2-3 times normal. The livers are enlarged when compared to normals but remain proportional to the increased mass. The much slower rate of obesity development and the lack of hyperglycemia, even transient, suggest that tubby is not allelic with either obese or diabetes. Allelism tests with these phenotypically similar genes are in progress. (D. L. Coleman, Eicher, and Southard) |
