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Myostatin overshoot
This abstract and the full study indicate that a powerful growth inhibitor myostatin increases significantly by day 56 in men administering testosterone. This may explain why most gains tend to plateau around week 8 or 9 of a standard cycle. The study indicates that myostatin returns to baseline around week 20 of a testosterone cycle so this gives us insight on how to design a cycle. Either run a 8 week cycle OR run 20 plus week cycles (stay on).
Myostatin is a gene, one of the units of heredity consisting of a sequence of deoxyribonucleic acid(DNA) that determines the inherited characteristics of every individual. It is a gene that contributes to the differentiation in growth factors, including physical size, and regulates muscle development.
Measurement of myostatin concentrations in human serum: Circulating concentrations in young and older men and effects of testosterone administration.
Lakshman KM, Bhasin S, Corcoran C, Collins-Racie LA, Tchistiakova L, Forlow SB, St Ledger K, Burczynski ME, Dorner AJ, Lavallie ER.
Section of Endocrinology, Diabetes, and Nutrition, Boston University School of Medicine, Boston Medical Center, 670 Albany Street, Boston, MA 02118, United States.
Methodological problems, including binding of myostatin to plasma proteins and cross-reactivity of assay reagents with other proteins, have confounded myostatin measurements. Here we describe development of an accurate assay for measuring myostatin concentrations in humans. Monoclonal antibodies that bind to distinct regions of myostatin served as capture and detector antibodies in a sandwich ELISA that used acid treatment to dissociate myostatin from binding proteins. Serum from myostatin-deficient Belgian Blue cattle was used as matrix and recombinant human myostatin as standard. The quantitative range was 0.15-37.50 ng/mL. Intra- and inter-assay CVs in low, mid, and high range were 4.1%, 4.7%, and 7.2%, and 3.9%, 1.6%, and 5.2%, respectively. Myostatin protein was undetectable in sera of Belgian Blue cattle and myostatin knockout mice. Recovery in spiked sera approximated 100%. ActRIIB-Fc or anti-myostatin antibody MYO-029 had no effect on myostatin measurements when assayed at pH 2.5. Myostatin levels were higher in young than older men (mean+/-S.E.M. 8.0+/-0.3 ng/mL vs. 7.0+/-0.4 ng/mL, P=0.03). In men treated with graded doses of testosterone, myostatin levels were significantly higher on day 56 than baseline in both young and older men; changes in myostatin levels were significantly correlated with changes in total and free testosterone in young men. Myostatin levels were not significantly associated with lean body mass in either young or older men. CONCLUSION: Myostatin ELISA has the characteristics of a valid assay: nearly 100% recovery, excellent precision, accuracy, and sufficient sensitivity to enable measurement of myostatin concentrations in men and women.
This abstract and the full study indicate that a powerful growth inhibitor myostatin increases significantly by day 56 in men administering testosterone. This may explain why most gains tend to plateau around week 8 or 9 of a standard cycle. The study indicates that myostatin returns to baseline around week 20 of a testosterone cycle so this gives us insight on how to design a cycle. Either run a 8 week cycle OR run 20 plus week cycles (stay on).
Myostatin is a gene, one of the units of heredity consisting of a sequence of deoxyribonucleic acid(DNA) that determines the inherited characteristics of every individual. It is a gene that contributes to the differentiation in growth factors, including physical size, and regulates muscle development.
Measurement of myostatin concentrations in human serum: Circulating concentrations in young and older men and effects of testosterone administration.
Lakshman KM, Bhasin S, Corcoran C, Collins-Racie LA, Tchistiakova L, Forlow SB, St Ledger K, Burczynski ME, Dorner AJ, Lavallie ER.
Section of Endocrinology, Diabetes, and Nutrition, Boston University School of Medicine, Boston Medical Center, 670 Albany Street, Boston, MA 02118, United States.
Methodological problems, including binding of myostatin to plasma proteins and cross-reactivity of assay reagents with other proteins, have confounded myostatin measurements. Here we describe development of an accurate assay for measuring myostatin concentrations in humans. Monoclonal antibodies that bind to distinct regions of myostatin served as capture and detector antibodies in a sandwich ELISA that used acid treatment to dissociate myostatin from binding proteins. Serum from myostatin-deficient Belgian Blue cattle was used as matrix and recombinant human myostatin as standard. The quantitative range was 0.15-37.50 ng/mL. Intra- and inter-assay CVs in low, mid, and high range were 4.1%, 4.7%, and 7.2%, and 3.9%, 1.6%, and 5.2%, respectively. Myostatin protein was undetectable in sera of Belgian Blue cattle and myostatin knockout mice. Recovery in spiked sera approximated 100%. ActRIIB-Fc or anti-myostatin antibody MYO-029 had no effect on myostatin measurements when assayed at pH 2.5. Myostatin levels were higher in young than older men (mean+/-S.E.M. 8.0+/-0.3 ng/mL vs. 7.0+/-0.4 ng/mL, P=0.03). In men treated with graded doses of testosterone, myostatin levels were significantly higher on day 56 than baseline in both young and older men; changes in myostatin levels were significantly correlated with changes in total and free testosterone in young men. Myostatin levels were not significantly associated with lean body mass in either young or older men. CONCLUSION: Myostatin ELISA has the characteristics of a valid assay: nearly 100% recovery, excellent precision, accuracy, and sufficient sensitivity to enable measurement of myostatin concentrations in men and women.
