Littermate controls

Younger (8 months) and older (19 months) male and female C57/B6 mice were purchased from the National Institute on Aging aged rodent colony. Male and Female rTg4510 mice and littermate controls (2 months of age) were purchased from the Jackson Laboratory. Mice were housed four per cage on a 12‐h light/dark cycle at 22–24°C at the laboratory animal facility at Colorado State University. All animals were given free access to water and food (Teklad Global Irradiated 18% protein rodent diet) and acclimatized to the facility before being randomly assigned to experimental groups. Body weights, food consumption, and water intake were measured every week, and all animals were routinely monitored by veterinary staff. All animal procedures were approved by Colorado State University, IACUC protocol #1441.

C57Bl/6J (000664), AR testicular feminization AR^tfm (001809) mice, which have a spontaneous mutation in the AR gene (54 (link), 55 (link)), and ERα knockout male and female (004744) mice were purchased from Jackson Laboratories. Appropriate background control mice and littermate controls from Jackson were used for genetic knockout models. Gonadectomized and sham surgery animals were purchased from Jackson Laboratories at 4 weeks of age. All mice were fed ad libitum either a control or an ND consisting of 13.5% fat (5LOD; LabDiet) or HFD consisting of 60% of calories from fat (Research Diets; D12492), starting at 6 weeks of age for 16 weeks of duration. Animals were housed in a specific pathogen-free facility with a 12-h light/12-h dark cycle and given free access to food and water. Animal protocols were in compliance with the Institute of Laboratory Animal Research Guide for the Care and Use of Laboratory Animals and approved by the University Committee on Use and Care of Animals at the University of Michigan (animal welfare assurance number: A3114-01). Metabolic cage studies were performed in singly housed animals in the Michigan Mouse Metabolic Phenotyping Center with evaluations for 3 days (13 (link)).