Studies of IGF-I and Klotho Protein in Relation to Anabolic-Androgenic Steroid and Growth Hormone Administrations

Mikael Lehtihet; Christina Stephanou; Annica Börjesson; Hasanuzzaman Bhuiyan; Anton Pohanka; Lena Ekström

doi:10.3389/fspor.2022.829940

Studies of IGF-I and Klotho Protein in Relation to Anabolic-Androgenic Steroid and Growth Hormone Administrations

Front Sports Act Living. 2022 Mar 31:4:829940. doi: 10.3389/fspor.2022.829940. eCollection 2022.

Authors

Mikael Lehtihet¹, Christina Stephanou², Annica Börjesson², Hasanuzzaman Bhuiyan³, Anton Pohanka^{2

3}, Lena Ekström²

Affiliations

¹ Department of Medicine, Karolinska Institutet, Stockholm, Sweden.
² Department of Laboratory Medicine, Karolinska Institutet, Stockholm, Sweden.
³ Doping Control Laboratory, Department of Clinical Pharmacology, Karolinska University Hospital, Huddinge, Sweden.

Abstract

It has been suggested to longitudinally monitor Insulin-like growth factor I (IGF-I) as a biomarker for the detection of recombinant growth hormone (GH). Subsequently, it is of interest to understand any confounders of endogenous IGF-I. Herein we have studied if serum IGF-I concentration is affected by the intake of anabolic androgenic steroids (AAS) and the potential connection between IGF-I and klotho protein. Moreover, the usefulness of klotho as a biomarker for recombinant GH intake was assessed in healthy male volunteers. An ongoing administration of AAS did not affect the levels of IGF-I. Klotho protein was ~30% higher in men with an ongoing AAS use compared to those with previous (>2 months ago) AAS use, and the serum klotho protein correlated negatively with luteinizing hormone (LH) (r _s = -0.38, p = 0.04) and follicle stimulating hormone (FSH) (r _s = -0.35, p = 0.05) levels. Serum IGF-I and klotho concentrations showed no correlation in the AAS using population but showed a strong negative correlation in healthy volunteers (r _s = -0.86, p = 0.006). The intake of recombinant GH did not affect the serum concentrations of the klotho levels. In conclusion, IGF-I was not affected by supra-physiological AAS doses in men. Interestingly, an association between AAS intake and serum klotho was seen. The usefulness of klotho as an androgen biomarker warrants further studies, whereas klotho can be discarded as a promising biomarker for GH doping.

Keywords: IGF-I; anabolic androgenic steroid; anti-doping; doping; growth hormone; klotho.