ACP5 and osteoporosis: Similarly, Alrowaili et al. (2021) found that in rats with glucocorticoid-induced osteoporosis that were subjected to intermittent fasting for 16–18 h per day for 90 days, the serum levels of the bone formation biomarkers, namely, osteoprotegerin, ALP, and osteocalcin, were significantly increased, and those of the bone resorption markers, namely, tartrate-resistant acid phosphatase (TRAP)-5b, amino-terminal cross-linking telopeptide of type-I collagen (NTX-1), and deoxypyridinoline (DPD), were significantly decreased.