title: Effect of endurance exercise on somatomedin-C/insulin-like growth factor I concentration in male and female runners.
abstract: By means of 3 endurance exercises, the effect of a several-hour intensive somatic stress on the changes of the Sm-C/IGF-I concentration was tested during, immediately after and on the day following the exercise. Exp. 1: Marathon with 17 male sportsmen in 2 groups with different glucose supply. Exp. 2: 45-km crosscountry run with 41 males. Exp. 3: Three 20-km runs with 8 young females at intervals of 3 months. In the marathon, no significant changes of the Sm-C/IGF-I concentration were found between the start, half distance and final values. The exogenous glucose supply (continuous or discontinuous) had also no effect. The tendency of a slight decrease of the Sm-C/IGF-I concentration by 0.14 U/ml (p greater than 0.05) was observed between start and finish in the 45 km crosscountry run lasting one hour longer. In the three 20-km runs, reproducible, slightly increased levels were measured at the end, whereas a decrease to the initial value or even below was detected on the following day (p greater than 0.05). The insignificant alterations of the Sm-C/IGF-I concentration measured in the 3 variants of races show that neither the hormonal changes stimulating the Sm-C/IGF-I synthesis (e.g. increase of GH and prolactin) nor inhibiting factors (energy deficiency) clearly dominate during strenuous exercises. The binding of carrier protein prevents great variations of the Sm-C/IGF-I level even under the condition of 3- to 4-hour extreme endurance exercises.
authors.affiliation: Children's Hospital, Friedrich-Schiller-University, Jena, GDR.
authors.forename: G
authors.initials: G
authors.lastname: Jahreis
authors.forename: V
authors.initials: V
authors.lastname: Hesse
authors.forename: H E
authors.initials: HE
authors.lastname: Schmidt
authors.forename: J
authors.initials: J
authors.lastname: Scheibe
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008297:Male; D010807:Physical Endurance / Q000502:physiology*; D012420:Running; D012737:Sex Factors; D013002:Somatomedins / Q000378:metabolism*; D013312:Stress, Physiological / Q000097:blood*
chemical_list: D013002:Somatomedins; D007334:Insulin-Like Growth Factor I