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The association between spontaneous pyelonephritis and maturity-onset diabetes mellitus in male MM mice
D M Taylor1, D L Neal, P A McBride
1AFRC & MRC Neuropathogenesis Unit, Edinburgh, United Kingdom.
Abstract:
Blood glucose and glucose tolerance tests demonstrated that many male MM mice are diabetic. Serial urine sampling showed that the diabetes occurred only in mature MM males and consisted of a single self-limiting episode. Histological examination of the pancreas, together with measurements of body weight, glycosylated haemoglobin and plasma insulin, revealed that the diabetes was of the maturity-onset insulin-resistant type. Bacteriological examination of the urine samples showed that urinary tract infection, a known feature of male MM mice, occurred in the diabetics but only after the onset of hyperglucosuria. It was concluded that the high urinary glucose levels of diabetic MM males are of prime importance in the aetiology of the renal infection which occurs rarely in non-diabetic MM males or in other strains in the colony. An infectious aetiology for the diabetes per se was excluded by the existence of diabetes in germfree MM males.
Insights
Male MM mice develop a self-limiting, maturity-onset insulin-resistant diabetes. High urinary glucose levels in these diabetic mice are crucial for causing urinary tract infections, not an infectious cause for diabetes.
Area of Science:
- Endocrinology
- Nephrology
- Microbiology
Background:
- Male MM mice exhibit a high prevalence of diabetes.
- Urinary tract infections are a known issue in male MM mice.
Purpose of the Study:
- To characterize the diabetes in male MM mice.
- To investigate the relationship between diabetes and urinary tract infections in this model.
Main Methods:
- Blood glucose and glucose tolerance tests.
- Serial urine sampling and bacteriological examination.
- Pancreatic histology, body weight, glycosylated hemoglobin, and plasma insulin measurements.
Main Results:
- Diabetes, characterized as maturity-onset insulin resistance, was confirmed in mature male MM mice.
- Diabetes presented as a single, self-limiting episode with hyperglucosuria.
- Urinary tract infections occurred in diabetic mice only after the onset of hyperglucosuria.
- An infectious etiology for the diabetes itself was ruled out in germfree MM mice.
Conclusions:
- Hyperglucosuria in diabetic male MM mice is a primary factor in the development of renal infections.
- The high urinary glucose levels are critical for the etiology of renal infections in this specific mouse strain.
- Diabetes in male MM mice is not caused by infection.