Yeast hydrolysate induces longitudinal bone growth and growth hormone release in rats

This study investigated the growth promoting effects of yeast extract (YH) fed to Sprague‐Dawley male rats (3 weeks old) for 4 weeks. The negative (N)‐control and positive (P)‐control groups were given a daily oral administration of saline and foremilk (1 g/kg of BW), respectively, and the YH‐1 and YH‐2 groups were given daily administrations of YH (0.5 and 1 g/kg of BW, respectively). After 4 weeks, the YH‐1, YH‐2 and P‐control groups showed significant differences in the body weight gain compared with the N‐control group ( p < 0.05). The YH‐1 and YH‐2 groups also had significantly different tibial bone growths (0.47 and 0.49 mm/day, respectively) and femur bone growths (0.52 and 0.53 mm/day, respectively) compared with the N‐control group (0.37 mm/day of tibial growth and 0.42 mm/day of femur growth) ( p < 0.05). The YH‐1 and YH‐2 groups had significantly different growth plate (proximal epiphysis) height increments (0.62 and 0.56 mm, respectively) compared with the N‐control group (0.17 mm) ( p < 0.05). Lastly, the YH‐1 and YH‐2 groups presented different growth hormone (GH) levels (1.77 and 2.10 ng/mL, respectively) than the N‐control group (0.82 ng/mL) ( p < 0.05). YH administration increased longitudinal bone growth and GH secretion in rats. Consequently, YH may offer an improved ability to treat GH deficiency‐related disorders. Copyright © 2008 John Wiley & Sons, Ltd.