IGF-1, IGFBP-3, GROWTH HORMONE AND TESTOSTERONE IN MALE AND FEMALE ATHLETES DURING BOVINE COLOSTRUM SUPPLEMENTATION

Abstract

The differences observed between males and females have classically been attributed to the higher concentrations of testosterone (TE) in males but the differences between genders in the concentrations of insulin-like growth factor 1 (IGF-1), IGF-binding protein 3 (IGFBP-3) and growth hormone (GH) are small or there are none. A question arises whether males and females respond similarly to bovine colostrum supplementation which has been shown to increase serum IGF-1 concentration in male athletes during a training period of eight days (Mero et al., J. Appl. Physiol. 83: 1144–1151,1997). PURPOSE: To examine the differences in serum concentrations or IGF-1, IGFBP-3, GH and TE during bovine colostrum supplementation in athletes during two weeks in a training season. METHODS: Adult active male (n = 10) and female (n = 9) athletes were supplemented with 20g bovine colostrum (Dynamic TM) a day during two weeks in a training season. The daily amount of 20g bovine colostrum included 74μg IGF-1. Blood samples were drawn from the antecubital vein in the morning at 0700–0800 after 10 h of fasting four times during the period to analyse serum IGF-1, IGFBP-3, GH and TE. RESULTS: The mean values of four measurements during two weeks showed that females had greater concentrations in IGF-1 (p < 0.05), IGFBP-3 (p < 0.01) and GH (p < 0.05) than males whereas males had as expected greater (p < 0.001) TE concentration than females. The increase in IGF-1 during two weeks was similar in both genders (19% in all subjects; p < 0.01). The concentration of IGFBP-3 decreased (p < 0.05–0.001) in both genders but GH decreased (p < 0.05) only in females. There were no changes in TE during two weeks either in males or females. CONCLUSION: During two weeks of bovine colostrum supplementation in a training season the serum concentration of GH decreases in female athletes but not in male athletes and in IGF-1, IGFBP-3 and TE there are no differences in concentration changes between genders. Supported by TEKES 40824/98.