| Pituitary volume in retired boxers, relative to growth hormone (GH) values | |||
| volume in boxers GH deficient | < | volume in boxers with normal GH | |
| Adrenocorticotropic hormone (ACTH) deficiency rate in retired or active amateur male boxers | |||
| 8% | |||
| Growth hormone (GH) | |||
| Mean peak GH levels | |||
| boxers | non-boxing controls | ||
| 10.9 ± 1.7 µg·l−1 | 41.4 ± µg·l−1 | ||
| Negative correlations | |||
| increasing boxing duration | ↔ | decreasing peak GH levels | |
| increasing number of bouts | ↔ | decreasing peak GH levels | |
| GH deficiency rates | |||
| both active and retired boxers | active boxers | retired boxers | |
| 15% of all the boxers | 1.6% of all the boxers | 13% of all the boxers, but 47% of the retired boxers | |
| Insulin-like growth factor-1 (IGF-1) mean levels | |||
| boxers | controls | ||
| 237 ± 23.3 ng·dl−1 | 367 ± 18.8 ng·ml−1 | ||
| Erythropoietin (EPO) values in non-iron-depleted boxers, post-training at moderate altitude (1800 m) | |||
| values increase in iron-treated boxers | = | values increase in placebo-treated boxers | |