(A) Serum total osteocalcin (Ocn) and insulin (Ins) levels in 3-month-old mice at rest or after exercise.

(B) Serum undercarboxylated Ocn (uncarb Ocn) levels in 3-month-old mice at rest (−1) and 0, 1, 2, and 4 hr after exercise.

(C) Serum CTX levels in 3-month-old mice at rest and after exercise.

(D) Serum OCN levels in women at rest and after exercise.

(E and F) Serum total and uncarb Ocn levels in female (E) and male (F) mice of various ages.

(G) Serum PINP in mice of various ages.

(H) Osteocalcin (Ocn) expression in femur in mice of various ages.

(I) Performance during an endurance test (running on a treadmill at 30 cm/s until exhausted) of 3-, 6-, and 12-month-old female WT mice.

(J) Serum uncarb Ocn levels in 3-, 6-, and 12-month-old female mice at rest and after exercise.

(K) Serum total Ocn levels in 2- to 33-year-old female and male rhesus macaque monkeys.

(L) Serum total OCN levels in women and men 11 to 78 years old.

(M–O) (M) Performance during an endurance test (running on a treadmill at 30 cm/s until exhausted) of 3-month-old and (N) 12- and 15-month-old WT mice treated with Ocn, and (O) 10-month-old WT mice receiving Ocn for 28 days.

(Exercise refers to 40 min running at 30 cm/s on a treadmill.) All data are presented as mean ± SEM.