The ratio of mouse insulin I:insulin II does not reflect that of the corresponding preproinsulin mRNAs
Biochemistry & Molecular Pharmacology
Graduate School of Biomedical Sciences; Department of Neurology
Life Sciences | Medicine and Health Sciences
Rats and mice both express two, non-allelic, insulin genes. In the rat the ratio of the two preproinsulin mRNAs closely matches that of the mature insulin peptides. The experiments reported here demonstrate that this is not the case in the mouse. The relative amounts of the two murine proinsulin RNAs were measured by an S1 nuclease assay. The ratio of preproinsulin I mRNA to preproinsulin II mRNA was 4:1 in RNA extracted from the pancreas of mice fed ad libitum or fasted for 72 h. A similar value was found in mouse islets of Langerhans after maintenance in tissue culture for 48 h at either 2.8 or 16.7 mM glucose. The ratio of insulin I:insulin II peptides, assessed by separating the two insulins using reversed phase high-performance liquid chromatography, was approximately 1:3 in both pancreas and islets. Thus in the mouse, unlike the rat, the ratio of the two insulin peptides does not reflect that of the two preproinsulin mRNAs.
Mol Cell Endocrinol. 1992 Aug;86(3):177-86.
Molecular and cellular endocrinology
Wentworth, Bruce Martin; Rhodes, Christopher J.; Schnetzler, Bruno; Gross, David J.; Halban, Phillippe A.; and Villa-Komaroff, Lydia, "The ratio of mouse insulin I:insulin II does not reflect that of the corresponding preproinsulin mRNAs" (1992). GSBS Student Publications. 1340.