Short-term 17-beta-estradiol administration does not affect metabolism in young males.
We have previously demonstrated that females oxidize more lipid and less protein and carbohydrate during endurance exercise [21]. Several studies in male rats have demonstrated similar metabolic changes after 4 d of 17-beta-estradiol (E2) administration. Our purpose was to study the effects of E2 administration upon substrate metabolism during 90min of cycle ergometry at 60% VO2peak in 11 healthy, young males. E2 was administered in a single-blind, cross-over, randomized fashion for 11 d (100 microg.d(-1) x 3.5d --> 200 microg.d(-1) x 3.5 d --> 300 microg.d(-1) x 4.0 d). Respiratory exchange ratio (RER), VO2, Ve, HR, lactate, and glucose were measured every 30 min during exercise and E2, testosterone TEST, glycerol and triglycerides were measured prior to exercise T = 0 min. Muscle biopsies were taken from the vastus lateralis before and after exercise for glycogen determination. Estradiol treatment resulted in lower plasma TEST (20.8-->7.8 nmol.L(-1), P<0.0001) and higher plasma E2 (168.1 327.3 pmol.L(-1), P < 0.002). Therewere no effects of E2 treatment upon any of the other measured variables including muscle glycogen: (E2 - PRE = 529.3 --> POST = 237.9; PL-PRE = 582.2 --> POST = 262.4 mmol.kg(-1) [dm]). We concluded that short-term E2 treatment increased plasma E2 to female follicular levels in males but had no effect upon lipid or carbohydrate metabolism.
Tarnopolsky
M A
MA
Department of Neurology, McMaster University, Hamilton, Ont., Canada. tarnopol@fhs.mcmaster.ca
Roy
B D
BD
MacDonald
J R
JR
McKenzie
S
S
Martin
J
J
Ettinger
S
S
D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D001786:Blood Glucose / Q000032:analysis; D050260:Carbohydrate Metabolism; D018592:Cross-Over Studies; D004958:Estradiol / Q000008:administration & dosage* / Q000097:blood; D006003:Glycogen / Q000032:analysis / Q000378:metabolism*; D006801:Humans; D019344:Lactic Acid / Q000097:blood; D050356:Lipid Metabolism; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism*; D010101:Oxygen Consumption / Q000187:drug effects; D010807:Physical Endurance / Q000187:drug effects* / Q000502:physiology; D012737:Sex Factors; D016037:Single-Blind Method; D013739:Testosterone / Q000097:blood; D014280:Triglycerides / Q000097:blood
D001786:Blood Glucose; D014280:Triglycerides; D019344:Lactic Acid; D013739:Testosterone; D004958:Estradiol; D006003:Glycogen