Intravenous estrogens increase insulin clearance and action in postmenopausal women.
To test the hypothesis that estrogens alter insulin action, we evaluated the effects of intravenous conjugated estrogens (CE) on insulin-stimulated steady-state glucose infusion rate (SSGIR) and suppression of plasma glycerol in postmenopausal women (mean +/- SD; 56 +/- 4 yr; n = 12) not using hormone replacement. SSGIR and glycerol were measured during a two-stage (8 and 40 mU. m-2. min-1) hyperinsulinemic euglycemic clamp on 2 days, with or without a 2.5-mg intravenous CE bolus. Serum estradiol concentrations were increased approximately 200% on the estrogen (EST) compared with the control (CON) days. Serum insulin was reduced (P < 0.01) during stage 2 of the clamp for EST (63.3 +/- 12.8 micro U/ml) vs. CON (78.2 +/- 15.8 micro U/ml). Mean SSGIR and plasma glycerol did not differ between CON and EST days. With adjustment for differences in insulin concentration between conditions, stage 2 glucose disposals were significantly higher (8.63 vs. 7.20 mg. kg-1. min-1) and plasma glycerol concentrations were significantly lower (29.4 vs. 35.0 micro mol/l) for EST vs. CON. Our findings suggest that acute CE administration increases insulin clearance and action in postmenopausal women.
Van Pelt
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4200 E. Ninth Ave., Box B179, Denver, CO 80262. rachael.vanpelt@uchsc.edu
Gozansky
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Schwartz
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Kohrt
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WM
D001823:Body Composition; D004958:Estradiol / Q000097:blood; D004966:Estrogens, Conjugated (USP) / Q000008:administration & dosage*; D005260:Female; D005947:Glucose / Q000008:administration & dosage; D015309:Glucose Clamp Technique; D005990:Glycerol / Q000097:blood; D006801:Humans; D006946:Hyperinsulinism; D007275:Injections, Intravenous; D007328:Insulin / Q000097:blood* / Q000494:pharmacology*; D007700:Kinetics; D008875:Middle Aged; D017698:Postmenopause
D004966:Estrogens, Conjugated (USP); D007328:Insulin; D004958:Estradiol; D005947:Glucose; D005990:Glycerol