Ovariectomized rat model for osteoporosis

Female Sprague–Dawley rats, 6 months old (Harlan, Indianapolis, IN) were maintained on a 12 h light/dark cycle at 22°C with ad libitum access to food (TD 89222 with 0.5% Ca and 0.4%P; Teklad, Madison, WI, USA) and tap water. Rats were ovariectomized (OVx) or subjected to sham surgery. OVx rats were allowed to lose bone mass for 1 month and randomized by body weight into groups of seven rats each. Rats were dosed every 6 days with vehicle or LY627‐2K (11, 33 or 110 nmol·kg⁻¹) or daily with PTH (1–38) (0.67 nmol·kg⁻¹), for 8 weeks. Lumbar vertebra were excised at necropsy and analysed by quantitative CT (Stratec) and then prepared for biomechanical testing. Strength was evaluated by loading excised vertebra to failure (Ma et al., 2011). Serum calcium was measured at the end of the 8 week study period for all rats.