TY - JOUR

T1 - Effect of administration of oral contraceptives on the synthesis and breakdown of myofibrillar proteins in young women

AU - Hansen, M

AU - Langberg, H.

AU - Holm, Lars

AU - Miller, B F

AU - Petersen, S.G.

AU - Doessing, Simon

AU - Skovgaard, D

AU - Trappe, T.

AU - Kjær, Michael

N1 - © 2009 John Wiley & Sons A/S.

PY - 2011

Y1 - 2011

N2 - Oral contraceptive (OC) treatment has an inhibiting effect on protein synthesis in tendon and muscle connective tissue. We aimed to investigate whether OC influence myofibrillar protein turnover in young women. OC-users (24±2 years; Lindynette® n=7, Cilest® n=4) and non-OC-users (controls, 24±4 years n=12) performed one-legged kicking exercise. The next day, the myofibrillar protein fractional synthesis rate (FSR) was measured using stable isotopic tracers ((13)C-proline) while the subjects were fed standardized nutrient drinks. Simultaneously, a marker for myofibrillar protein breakdown, 3-methyl-histidine (3-MH), was measured in the interstitial fluid of the vastus lateralis. Measurements were performed in both legs. In general, myofibrillar protein FSR was lower in OC-users (two-way analysis of variance, P<0.05), although the difference seemed to depend on the OC type. Interstitial 3-MH in the skeletal muscle was not different between groups and did not vary by OC type. Exercise did not change myofibrillar protein FSR or 3-MH concentrations. Serum androstenedione and bioavailability of testosterone were lower in OC-users. In conclusion, the results indicate that the use of OC has an inhibiting effect on myofibrillar protein synthesis and the magnitude of the effect may depend on the type of OC. In contrast, there was no effect of OC on myofibrillar protein breakdown in the fed state.

AB - Oral contraceptive (OC) treatment has an inhibiting effect on protein synthesis in tendon and muscle connective tissue. We aimed to investigate whether OC influence myofibrillar protein turnover in young women. OC-users (24±2 years; Lindynette® n=7, Cilest® n=4) and non-OC-users (controls, 24±4 years n=12) performed one-legged kicking exercise. The next day, the myofibrillar protein fractional synthesis rate (FSR) was measured using stable isotopic tracers ((13)C-proline) while the subjects were fed standardized nutrient drinks. Simultaneously, a marker for myofibrillar protein breakdown, 3-methyl-histidine (3-MH), was measured in the interstitial fluid of the vastus lateralis. Measurements were performed in both legs. In general, myofibrillar protein FSR was lower in OC-users (two-way analysis of variance, P<0.05), although the difference seemed to depend on the OC type. Interstitial 3-MH in the skeletal muscle was not different between groups and did not vary by OC type. Exercise did not change myofibrillar protein FSR or 3-MH concentrations. Serum androstenedione and bioavailability of testosterone were lower in OC-users. In conclusion, the results indicate that the use of OC has an inhibiting effect on myofibrillar protein synthesis and the magnitude of the effect may depend on the type of OC. In contrast, there was no effect of OC on myofibrillar protein breakdown in the fed state.

KW - Analysis of Variance

KW - Contraceptives, Oral

KW - Energy Intake

KW - Exercise Test

KW - Female

KW - Humans

KW - Leg

KW - Methylhistidines

KW - Muscle Proteins

KW - Muscle, Skeletal

KW - Myofibrils

KW - Proline

KW - Young Adult

U2 - 10.1111/j.1600-0838.2009.01002.x

DO - 10.1111/j.1600-0838.2009.01002.x

M3 - Journal article

C2 - 19883384

VL - 21

SP - 62

EP - 72

JO - Scandinavian Journal of Medicine & Science in Sports

JF - Scandinavian Journal of Medicine & Science in Sports

SN - 0905-7188

IS - 1

ER -