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Objective: We assessed insulin sensitivity in women comparing the insulin tolerance test (ITT) with the intravenous glucose tolerance test with frequent sampling and computer modeling (FSIVGTT) and evaluated the effects of hormonal therapy in postmenopausal women using both methods., Methods: This prospective study tested 18 premenopausal women and ten postmenopausal women randomized to receive either estrogen alone or estrogen with a sequential progestin for 6 months at a menopause research clinic. All subjects received an ITT and an FSIVGTT within 48-72 hours of each other in random sequence. Postmenopausal women were then randomized to receive either 0.625 mg conjugated equine estrogen for 6 months or 0.625 mg conjugated equine estrogen with medroxyprogesterone acetate, 10 mg, for 10 days each month for 6 months. Both the ITT and the FSIVGTT were repeated following hormonal therapy at 2 and 6 months. Plasma insulin and glucose were measured; insulin sensitivity was calculated after the ITT (Kitt) and the FSIVGTT (Si) at each visit in each group., Results: A close correlation was found between Kitt and Si values at initial testing in both pre- and postmenopausal women and following both types of hormonal therapy (r = 0.76 for all tests, P < .001). A reduction in insulin sensitivity was observed in postmenopausal compared to premenopausal women; this occurred in five of ten postmenopausal women using the Kitt measurement and in four of ten women using Si. Estrogen replacement had a beneficial effect on insulin sensitivity. While Kitt increased by 24.2 +/- 9.6% (P < .05), the increase in Si (6.7 +/- 18%) was not significant because of the variability with this measurement. An attenuation in insulin sensitivity was seen with added progestin. Kitt values decreased by 17.7 +/- 7.7% and Si values by 31.9 +/- 12%. Similar findings were noted at 2 and 6 months., Conclusions: The ITT and FSIVGTT provide quantitatively similar information regarding insulin sensitivity in healthy women. A mild degree of insulin resistance appears to be present in some healthy postmenopausal women. Estrogen appears to improve insulin sensitivity, while added progestin may attenuate this beneficial effect.

Objective: We assessed the effects of progestin when added to estrogen on the adaptive patterns to provoked stress in postmenopausal women., Methods: Fourteen postmenopausal women were randomized to receive either a transdermal estrogen patch (TE2) (n = 7) for 6 weeks or TE2 with added medroxyprogesterone acetate (10 mg) (TE2/MPA) (n = 7) for the last 10 days of the 6-week regimen. Behavioral stress tests were administered to each group, with measurements of biophysical and neuroendocrine responses. In a crossover fashion, after each group received the first treatment and testing, treatment was continued for another 6 weeks with the alternate regimen, at which time another stress test was administered. Responses to stress in the two treatment groups were compared to each other and to established placebo responses., Results: Biophysical responses in the TE2 group were significantly blunted compared to both TE2/MPA and placebo responses (P < .05). Without MPA treatment, there were significantly blunted speech (P < .05) and cold pressor (P < .01) blood pressure responses. With added progestin, there was a greater systolic blood pressure response (P < .01) compared with estrogen alone. Both groups (TE2 and TE2/MPA) had blunted and nonsignificant responses of ACTH and cortisol upon testing, whereas the placebo group showed a significant response (P < .01). Plasma norepinephrine responses, however, were significantly blunted after TE2, compared with the increased responses observed with both TE2/MPA and placebo (P < .01)., Conclusion: Although estrogen significantly reduces behaviorally induced stress reactivity in postmenopausal women, certain doses of progestin administration may blunt this effect.

Objective: We determined the independent effects of various doses of ethinyl estradiol used in oral contraceptives or norethindrone acetate, as well as their combination, on insulin sensitivity in normal women., Study Design: Thirty-three normal ovulatory female volunteers were recruited for this study. Insulin tolerance tests were performed after carbohydrate loading to determine the kinetic disappearance of glucose and insulin. After initial testing the women were randomized into four groups: ethinyl estradiol 20 micrograms, 35 micrograms, and 50 micrograms and norethindrone 1 mg. Insulin tolerance tests were repeated after 1 month of treatment and again after a second month, when all ethinyl estradiol groups received the addition of norethindrone 1 mg to their doses of ethinyl estradiol. Plasma glucose and insulin were measured, and insulin sensitivity (K(itt) glucose) and the disappearance of insulin (K(itt) insulin) were calculated., Results: All groups were comparable at baseline, and no significant changes in fasting glucose and insulin were evident with treatment. After ingestion of 50 micrograms ethinyl estradiol the K(itt) glucose value decreased significantly (p < 0.03) and ingestion of 20 micrograms and 35 micrograms showed individual changes, but as groups the changes were not statistically significant. All ethinyl estradiol groups combined had a significant decrease in K(itt) glucose (p < 0.01). Norethindrone 1 mg alone did not change K(itt) glucose values, and after the addition of norethindrone to ethinyl estradiol, K(itt) glucose values normalized. K(itt) insulin values were also lower with treatment but were lower with ethinyl estradiol plus norethindrone compared with ethinyl estradiol alone (p < 0.04), suggesting an attenuation of insulin clearance with the progestin., Conclusion: Ethinyl estradiol alone decreases insulin sensitivity, and this may occur at lower doses, but norethindrone 1 mg does not appear to do so. However, progestins may alter insulin clearance.

Objective: Our purpose was to determine the pattern of reactivity to stress in premenopausal and postmenopausal women and to assess the effects of estrogen., Study Design: A behavioral stress test was given to premenopausal (n = 13) and postmenopausal women (n = 36). Biophysical and neuroendocrine responses were measured during and on completion of the stress test. The postmenopausal women were then randomized to placebo or transdermal estradiol treatment for 6 weeks, at which time another behavioral stress test was given., Results: Stress reactivity to math and speech tasks elicited significantly greater systolic blood pressure responses in postmenopausal women compared with premenopausal women (p < 0.05). On retesting, significant biophysical responses that were present during the initial stress testing were still present (p < 0.05) in the placebo group but were blunted with estrogen treatment. Plasma corticotropin, cortisol, androstenedione, and norepinephrine increased during testing to a similar degree in premenopausal and postmenopausal women; this response was maintained after placebo treatment. Postmenopausal women treated with estrogen had blunted responses., Conclusion: Significant differences in responses to psychologic stress exist in premenopausal and postmenopausal women. The lack of adaptation may account in part for the increased risk of cardiovascular disease in postmenopausal women. Estrogen appears to blunt the stress-induced response.

Because smoking is associated with an increased risk of osteoporosis, yet a decreased risk of endometrial carcinoma, a state of relative hypoestrogenism induced by smoking has been suggested. However, because previous data are unclear and do not reflect current trends in smoking intensity and estrogen prescriptions, we examined the estrogen profiles of postmenopausal women, by smoking status, both before and after oral micronized estradiol. Baseline levels of estrone, estradiol, estrone sulfate, and estrone glucuronide were similar in nonsmokers and smokers, but unbound (non-sex-hormone-binding-globulin--bound) estradiol was significantly lower in smoking women (p less than 0.05) and sex-hormone-binding-globulin--binding capacity was higher (p less than 0.001). After 1 or 2 mg of micronized estradiol, estrone and estradiol serum profiles were similar but unbound estradiol was significantly lower in women who were smokers (p less than 0.05). Serum estrone glucuronide rose with treatment but was indistinguishable in nonsmokers and smokers. However, maximum changes in serum estrone sulfate were greater in smokers after administration of estrogen, suggesting a hepatic effect. Urinary estrone glucuronide levels increased after 8 hours of oral estrogen but were similar in nonsmokers and smokers with the two doses. It appears that even moderate smoking, as studied here, induces significant changes in hepatic estrogen metabolism and is best reflected by alterations in serum estrone sulfate and sex-hormone-binding-globulin--binding capacity that result in decreased serum unbound estradiol. However, these changes do not appear to require increasing the estrogen dosage to achieve physiologic levels of estrogen in postmenopausal smokers.

We compared the transdermal and subdermal routes of estrogen administration with respect to the constancy of estrogen delivery and metabolic effects. Twenty postmenopausal women were randomized to receive either two 25 mg estradiol pellets subdermally (n = 10) or a 0.1 mg estradiol transdermal patch twice weekly (n = 10). Blood was sampled at 0, 2, 4, 6, 8, 12, 24, and 72 hours and 1, 2, 4, 8, 12, 16, 20, and 24 weeks (fasting samples at 0, 12, and 24 weeks), and a fasting urine was obtained after diuresis at 0, 12, and 24 weeks. In a 72-hour profile, serum estradiol levels (mean +/- SE) were highest at 24 hours (179 +/- 20 pg/ml) and fell to 139 +/- 16 pg/ml at 72 hours in the pellet group. In the patch group, estradiol levels rose rapidly to 152 +/- 33 pg/ml at 4 hours, remained relatively constant over 8 hours, and fell to 46 +/- 10 pg/ml at 72 hours. At 1 week, estradiol levels in the pellet group were 113 +/- 12 pg/ml and remained relatively constant for 24 weeks. In contrast, estradiol levels in the patch group were 52 +/- 11 pg/ml at 1 week and then varied widely until 24 weeks, when the levels were 89 +/- 26 pg/ml. The mean estradiol/estrone ratio ranged between 1 and 2.5 in both groups but fluctuated widely in the patch group. Follicle-stimulating hormone was suppressed in both groups; however, the decrement in the pellet group was greater (p less than 0.002). There was a significant increase in high-density lipoprotein cholesterol and a decrease in total cholesterol/high-density lipoprotein cholesterol at 12 weeks with the pellet but only at 24 weeks with the patch. The urinary calcium/creatinine ratio was reduced more consistently with the pellet than with the patch. Hot flushes were eliminated in all subjects.

Cessation of ovarian function is associated with a marked increased in morbidity and mortality secondary to ischemic heart disease. Estrogen replacement has been shown to impart protection against ischemic heart disease. We hypothesized that estrogen may influence vascular production of vasodilators such as prostacyclin. To investigate this relationship we have measured the production of 6-keto-prostaglandin F1 alpha, and thromboxane B2 by superfused uterine arteries from pre- and postmenopausal women. Arterial specimens from healthy normotensive premenopausal (n = 5) and postmenopausal women (n = 5) were superfused for 5 hours. Production of 6-keto-prostaglandin F1 alpha reached steady state levels by 120 minutes and remained linear for the length of the experiment. Indomethacin (4 x 10(-5) mol/L) added at 120 minutes significantly decreased prostanoid production. In subsequent experiments, 17 beta-estradiol in concentrations of 10, 100, 1000 ng/ml was added to the superfusion media at 120 minutes. Total production of 6-keto-prostaglandin F1 alpha by premenopausal arteries superfused with neat media during the steady state interval (3 hours) was significantly greater than that of postmenopausal specimens (1.25 versus 0.27 ng/mg dry tissue, p less than 0.05). Thromboxane B2 levels were undetectable in spent media. However, the addition of 17 beta-estradiol did not alter production of 6-keto-prostaglandin F1 alpha. These data suggest that arterial production of prostacyclin is significantly decreased in uterine arteries from postmenopausal women, but in this in vitro model system estrogens did not affect vascular prostanoid production.