Nelson Vergel
Founder, ExcelMale.com
This recent study reinforces the conclusion made by a study discussed in the first post of this thread. Low estradiol can cause increased fat mass.
Short-Term Estrogen Withdrawal Increases Adiposity in Healthy Men -
See more at: http://press.endocrine.org/doi/abs/10.1210/jc.2016-1482#sthash.YLNL077Q.dpuf
Abstract
Context:
Testosterone deprivation increases risk of insulin resistance in men, but whether this risk is independent of changes in body composition is unknown. Further, the metabolic roles of testosterone and its metabolite estradiol have not been clearly defined in men.
Objective:
To establish the effects of selective sex steroid withdrawal on insulin sensitivity in healthy men
Design:
Double-blinded, placebo-controlled, randomized trial
Setting:
Academic medical center
Participants:
56 healthy men, 19–55 years of age
Interventions:
Subjects received the GnRH antagonist acyline plus one of the following: placebo gel (Castrate), 1.25g testosterone gel (Low T/E), 5g testosterone gel (Normal T/E), or 5g testosterone gel with letrozole (Normal T/Low E) daily for 4 weeks. Body composition and glucose tolerance were assessed at baseline and end-of-treatment.
Main Outcome Measure:
Insulin sensitivity quantified by the Matsuda index
Results:
Predicted circulating sex steroid concentrations were achieved in all treatment groups. The time-by-group interaction for Matsuda index did not achieve significance in overall repeated measures analysis of variance (baseline vs. week 4, p=0.16). A significant time-by-group interaction was observed for fat mass (p=0.003), with changes in fat mass attributable predominantly to estrogen exposure in linear regression analysis (p=0.016). A time-by-group interaction also was observed for lean mass (p=0.03) and influenced by androgen exposure (p=0.003).
Conclusions:
Short-term sex steroid withdrawal in healthy men causes adverse changes in body composition. These findings support the role of estradiol as a determinant of adiposity in men.
Affiliations
1Center for Research in Reproduction and Contraception and
2Diabetes Institute, Division of Metabolism, Endocrinology, and Nutrition and
3Division of Gerontology & Geriatric Medicine, Department of Medicine, University of Washington School of Medicine
4The Fred Hutchinson Cancer Research Center; and
5the Geriatric Research, Education and Clinical Center, V.A. Puget Sound Health Care System, Seattle, WA
- See more at: http://press.endocrine.org/doi/abs/10.1210/jc.2016-1482#sthash.YLNL077Q.dpuf
Short-Term Estrogen Withdrawal Increases Adiposity in Healthy Men -
See more at: http://press.endocrine.org/doi/abs/10.1210/jc.2016-1482#sthash.YLNL077Q.dpuf
Abstract
Context:
Testosterone deprivation increases risk of insulin resistance in men, but whether this risk is independent of changes in body composition is unknown. Further, the metabolic roles of testosterone and its metabolite estradiol have not been clearly defined in men.
Objective:
To establish the effects of selective sex steroid withdrawal on insulin sensitivity in healthy men
Design:
Double-blinded, placebo-controlled, randomized trial
Setting:
Academic medical center
Participants:
56 healthy men, 19–55 years of age
Interventions:
Subjects received the GnRH antagonist acyline plus one of the following: placebo gel (Castrate), 1.25g testosterone gel (Low T/E), 5g testosterone gel (Normal T/E), or 5g testosterone gel with letrozole (Normal T/Low E) daily for 4 weeks. Body composition and glucose tolerance were assessed at baseline and end-of-treatment.
Main Outcome Measure:
Insulin sensitivity quantified by the Matsuda index
Results:
Predicted circulating sex steroid concentrations were achieved in all treatment groups. The time-by-group interaction for Matsuda index did not achieve significance in overall repeated measures analysis of variance (baseline vs. week 4, p=0.16). A significant time-by-group interaction was observed for fat mass (p=0.003), with changes in fat mass attributable predominantly to estrogen exposure in linear regression analysis (p=0.016). A time-by-group interaction also was observed for lean mass (p=0.03) and influenced by androgen exposure (p=0.003).
Conclusions:
Short-term sex steroid withdrawal in healthy men causes adverse changes in body composition. These findings support the role of estradiol as a determinant of adiposity in men.
Affiliations
1Center for Research in Reproduction and Contraception and
2Diabetes Institute, Division of Metabolism, Endocrinology, and Nutrition and
3Division of Gerontology & Geriatric Medicine, Department of Medicine, University of Washington School of Medicine
4The Fred Hutchinson Cancer Research Center; and
5the Geriatric Research, Education and Clinical Center, V.A. Puget Sound Health Care System, Seattle, WA
- See more at: http://press.endocrine.org/doi/abs/10.1210/jc.2016-1482#sthash.YLNL077Q.dpuf
