The glucose tolerance test in mice: Sex, drugs and protocol

Abstract

Aim: To establish the impact of sex, dosing route, fasting duration and acute habituation stress on glucose tolerance test (GTT) measurements used in the preclinical evaluation of potential glucose-modulating therapeutics.Methods: Adult male and female C57Bl/6J mice, implanted with HD-XG glucose telemetry devices, were fasted for 16 hours or 6 hours following acute habituation stress due to whole cage change, cage change with retention of used bedding or no cage change prior to intraperitoneal (IP) GTTs. To evaluate protocol refinement and sex on the ability of the GTT to detect drug effects, we administered 250 mg/kg oral metformin or 10 nmol/kg IP exendin-4 using optimized protocols.Results: Female mice were less sensitive to human intervention when initiating fasting. Following a 6-hour fast, retention of bedding whilst changing the cage base promotes quicker stabilization of basal blood glucose in both sexes. Prolonged fasting for 16 hours resulted in an exaggerated GTT response but induced pronounced basal hypoglycaemia. Following GTT protocol optimization the effect of exendin-4 and metformin was equivalent in both sexes, with females showing a more modest but more reproducible GTT response.Conclusions: Variations in GTT protocol have profound effects on glucose homeostasis. Protocol refinement and/or the use of females still allows for detection of drug effects, providing evidence that more severe phenotypes are not an essential prerequisite when characterizing/validating new drugs.

Low-Dose Chidamide Treatment Displays Sex-Specific Differences in the 3xTg-AD Mouse

“…Chidamide-treated females showed a trend towards improved glucose tolerance ( t (8) = 1.38, p = 0.21), but this did not reach significance ( Figure 1 A). Of note, females displayed greater variability in glucose tolerances, with AUC ranging from 200 to nearly 600, which may be due to hormonal variations [ 29 ]. A recent study reported female mice to be more glucose-tolerant than males and less sensitive to blood glucose fluctuations than males given various stressors [ 29 ].…”

TEAD1, MYO7A and NDUFC2 are novel functional genes associated with glucose metabolism in BXD recombinant inbred population

“…71,72 Nevertheless, compared with male mice, female mice showed different susceptibilities and responses under various experimental conditions because of hormonal fluctuations, such as being less glucose-intolerant and insulin-resistant. 73,74 In addition, our in vitro validation studies have shown that the genes TEAD1, MYO7A and NDUFC2 were associated with the insulin signalling pathway and hepatic glucose metabolism; however, their detailed regulatory mechanisms still need further study in vivo.…”

In vivo techniques for assessment of insulin sensitivity and glucose metabolism

“…Furthermore, we have discussed key factors that can affect glucose metabolism, such as fasting duration and sex of the rodents. Other factors that may cause stress and alter glucose metabolism have begun to be described in the literature, such as temperature, method of cage change, and even the sex of the scientist ( Sorge et al 2014 , Drucker 2016 , Georgiou et al 2022 , Kennard et al 2022 ). Regarding the latter, stress responses in mice vary depending on the sex of the investigator handling the mice and merely because men and women give off different scents ( Sorge et al 2014 , Georgiou et al 2022 ).…”