The blunting of the thyrotropin response to repeated thyrotropin-releasing hormone administration is reduced by dopaminergic blockade both at normal and elevated serum levels of thyroid hormones

1990 ◽  
Vol 123 (5) ◽  
pp. 519-525 ◽  
Author(s):  
Eva Marie T. Erfurth ◽  
Robyn Attewell ◽  
L. Pavo Hedner
Keyword(s):  
Menstrual Cycle ◽  
Elevated Serum ◽  
Premenopausal Women ◽  
Serum Levels ◽  
Follicular Phase ◽  
Serum Estradiol ◽  
Trh Test ◽  
Serum Estradiol Level ◽  
Hormone Administration ◽  
Estradiol Levels

Abstract. Fifteen premenopausal women were investigated in the follicular phase of the menstrual cycle with two TRH tests within an interval of 48 to 96 h. Ninety min before each TRH test either 10 mg metoclopramide or saline was injected iv in randomized order. The same procedure was repeated in the following menstrual cycle after pretreatment with T4 (0.5 mg daily for 6-14 days). At least 2 months later the same procedure was repeated with T3 pretreatment (60-120 μg for 6-8 days) in 9 of them. A multiple regression analysis was used in modelling the relationships between TSH release and serum free T3, T4 and estradiol levels, adjusting for the presence of metoclopramide and the order of the test. No correlation was found between the TSH response to TRH and the serum estradiol level. The TSH response to the second TRH test was approximately half the first one, both in the control situation and after treatment with T4 or T3. The blunting of the TSH response to the second TRH administration was significantly reduced by metoclopramide, both at normal and elevated thyroid hormone levels, suggesting that a dopaminergic mechanism takes part in the blunting.

scholarly journals Quantitation of P450 aromatase immunoreactivity in human ovary during the menstrual cycle: relationship between the enzyme activity and immunointensity.

1994 ◽  
Vol 42 (12) ◽  
pp. 1565-1573 ◽  
Author(s):  
T Suzuki ◽  
H Sasano ◽  
H Sasaki ◽  
T Fukaya ◽  
H Nagura
Keyword(s):  
Menstrual Cycle ◽  
Enzymatic Activity ◽  
Corpus Luteum ◽  
Granulosa Cell ◽  
Granulosa Cells ◽  
Luteal Phase ◽  
Follicular Phase ◽  
Serum Estradiol ◽  
Human Ovary ◽  
Serum Estradiol Level

To understand changes associated with the menstrual cycle in the human ovary, it is very important to examine chronological changes in P450 aromatase (P450arom) enzymatic activity in the normal cycling ovary. Therefore, we initially examined the correlation between intensity of P450arom immunoreactivity and its biochemical enzymatic activity in five estrogen-producing human cancer cell lines (HHUA, Ishikawa, HEC-59, OMC-2, and MCF-7). P450arom immunointensity per cell was evaluated by the CAS 200 computed image analysis system, and its catalytic activity per 10(6) culture cells was analyzed by the tritiated water method. A significant correlation (r = 0.959) was demonstrated between P450arom immunoreactivity and enzymatic activity under optimal conditions of tissue fixation and immunohistochemical procedures. We then investigated P450arom immunointensity in 31 specimens of normal cycling human ovaries to examine chronological changes in P450arom activity per cell throughout the menstrual cycle. In the follicular phase, P450arom was observed in the granulosa cells of one selected antral follicle per case during the mid- to late proliferative period, and its immunointensity per granulosa cell in the follicle was not significantly different between mid- and late proliferative periods, although serum estradiol level was markedly elevated in the late proliferative period. In the luteal phase, both P450arom immunointensity per luteinized granulosa cell in a corpus luteum and serum estradiol level reached a peak in the mid-secretory period. These findings indicate that different factors may influence ovarian P450arom activity during the follicular and luteal phases, i.e., an increased number of granulosa cells in the selected follicle during the follicular phase but changes in P450arom activity per luteinized granulosa cell in the corpus luteum during the luteal phase.

scholarly journals Effects of estradiol on measurements of conduit artery endothelial function after ischemia and reperfusion in premenopausal women

2016 ◽  
Vol 94 (12) ◽  
pp. 1304-1308 ◽  
Author(s):  
Mary Clare Luca ◽  
Andrew Liuni ◽  
Paula Harvey ◽  
Susanna Mak ◽  
John D. Parker
Keyword(s):  
Menstrual Cycle ◽  
Ischemia Reperfusion ◽  
Premenopausal Women ◽  
Follicular Phase ◽  
Flow Mediated Dilatation ◽  
Before And After ◽  
Early Follicular Phase ◽  
First Time ◽  
Late Follicular Phase ◽  
Estradiol Levels

In premenopausal women, ovarian steroids are felt to play a role in the prevention of cardiovascular disease. We aimed to assess whether menstrual cycle variations in estrogen can modify the response to ischemia–reperfusion (IR) injury in humans. In an investigator-blinded crossover study, 10 healthy premenopausal women with regular menstrual cycles were studied. They had flow-mediated dilatation (FMD) measured by ultrasound in the radial artery before and after IR (15 min of brachial artery ischemia, 15 min of reperfusion) during both the early and late follicular phases of the menstrual cycle. The order of these visits was not randomized. IR significantly blunted FMD in the early follicular phase (pre-IR: 7.1% ± 1.0%; post-IR: 3.6% ± 1.0%, P = 0.01) when estradiol levels were low (148.4 ± 19.8 pmol/L). Conversely, FMD was preserved after IR during the late follicular phase (pre-IR: 7.2% ± 0.9%; post-IR: 7.0% ± 0.8%, P = NS, P = 0.03 compared with early follicular) when estradiol levels were high (825.7 ± 85.8 pmol/L, P < 0.001 compared with early follicular). There was a significant inverse relationship between estradiol concentration and IR-induced endothelial dysfunction (i.e., change in FMD after IR) (r = 0.59, r2 = 0.36, P < 0.01). These findings demonstrate, for the first time in humans, a clear relationship between the cyclical changes in serum concentrations of estradiol and the endothelium’s response to IR.

APC resistance during the normal menstrual cycle

2007 ◽  
Vol 98 (12) ◽  
pp. 1246-1251 ◽  
Author(s):  
Angela Silveira ◽  
Stella Thomassen ◽  
Jacob Odeberg ◽  
Anders Hamsten ◽  
Jan Rosing ◽  
...  
Keyword(s):  
Menstrual Cycle ◽  
Protein C ◽  
Activated Protein C ◽  
Serum Levels ◽  
Serum Estradiol ◽  
Menstrual Cycles ◽  
Apc Resistance ◽  
Exogenous Estrogen ◽  
Normal Menstrual Cycle ◽  
Estradiol Concentration

SummaryIncreased serum levels of endogenous as well as exogenous estrogen are regarded to be responsible for acquired activated protein C (APC) resistance. It was the objective of this study to evaluate whether the physiological increase in serum estradiol concentration during the normal menstrual cycle affects the individual’s sensitivity to APC. Seventy-two women with normal menstrual cycles were included in the study. Blood samples for analysis of estradiol (E2), progesterone (P4) and APC resistance were drawn at two time points of the menstrual cycle (day 3–5 and day 22–25). Two methods of measuring APC resistance were used: the activated partial thromboplastin time (aPTT)-based assay and the endogenous thrombin potential (ETP)-based APC resistance test. Independent of the method used, no changes in APC resistance were found, even though the E2 concentration increased significantly between the two menstrual phases. No correlations between E2 levels and APC resistance, P4 levels and APC resistance or changes in E2 concentrations and changes in APC resistance were detected. Ten women were carriers of the factor VLeiden mutation. Their baseline APC resistance was increased, but their response to elevated E2 during the menstrual cycle did not differ from that of non-carriers. In conclusion, our observations suggest that physiological differences in serum levels of estradiol and progesterone between the early follicular and the luteal phase in a normal menstrual cycle do not have any significant impact on the individual’s sensitivity to APC.

Comparison of effects of sustained isocapnic hypoxia on ventilation in men and women

1997 ◽  
Vol 83 (2) ◽  
pp. 599-607 ◽  
Author(s):  
Dimitar Sajkov ◽  
Alister Neill ◽  
Nicholas A. Saunders ◽  
R. Douglas McEvoy
Keyword(s):  
Menstrual Cycle ◽  
Minute Ventilation ◽  
Premenopausal Women ◽  
Follicular Phase ◽  
Inspiratory Time ◽  
Men And Women ◽  
Ventilatory Responses ◽  
Reduced Frequency ◽  
Normal Men ◽  
Respiratory Depressant

Sajkov, Dimitar, Alister Neill, Nicholas A. Saunders, and R. Douglas McEvoy. Comparison of the effects of sustained isocapnic hypoxia on ventilation in men and women. J. Appl. Physiol. 83(2): 599–607, 1997.—Sleep-related respiratory disturbances are more common in men than in premenopausal women. This might, in part, be due to different susceptibilities to the respiratory depressant effects of hypoxia. Therefore, we compared ventilation during 10 min of baseline room-air breathing and 20-min sustained isocapnic hypoxia (fractional inspired O2 = 11%, arterial saturation of O2 ≈ 80%) followed by 10 min of breathing 100% O2 in 10 normal men and in 10 women in the follicular phase of the menstrual cycle. Control measurements were made during two transitions from room air (10 min) to 100% O2 (10 min) and averaged. Inspired minute ventilation (V˙i) after 2 min of hypoxia was the same in men and women [131 ± 6.1% baseline for men, 136 ± 7.7% baseline for women; not significant (NS)] and declined to the same level after 20 min (115 ± 5.0% baseline for men, 116 ± 6.6% baseline for women; NS) associated with a similar decline in inspiratory time and tidal volume. Breathing frequency did not change.V˙i decreased transiently during subsequent 100% O2 breathing in both men and women, associated with reduced frequency and duty cycle and increased expiratory time. The fall inV˙i was significantly greater than that observed during control hyperoxia experiments in men but not in women. We conclude that ventilatory responses to sustained isocapnic hypoxia do not differ between awake healthy men and women in the follicular phase of their menstrual cycle. However, after termination of isocapnic hypoxia, men appear to depress their ventilation to a greater degree than women.

Effects of menstrual cycle and menopause on internal carotid artery shear-mediated dilation in women

2020 ◽  
Author(s):  
Erika Iwamoto ◽  
Rintaro Sakamoto ◽  
Wakako Tsuchida ◽  
Kotomi Yamazaki ◽  
Tatsuki Kamoda ◽  
...  
Keyword(s):  
Menstrual Cycle ◽  
Carotid Artery ◽  
Internal Carotid Artery ◽  
Endothelial Function ◽  
Internal Carotid ◽  
Premenopausal Women ◽  
Cycle Phase ◽  
Serum Estradiol ◽  
Cross Sectional ◽  
Potential Index

This study aimed to elucidate the effects of change in estrogen during the menstrual cycle and menopause on shear-mediated dilation of the internal carotid artery (ICA), a potential index of cerebrovascular endothelial function. Shear-mediated dilation of the ICA and serum estradiol were measured in 11 premenopausal (Pre-M, 21±1yrs), 13 perimenopausal (Peri-M, 49±2yrs), and 10 postmenopausal (Post-M, 65±7yrs) women. Measurements were made twice within the Pre-M group at their early follicular (EF, lower estradiol) and late follicular (LF, higher estradiol) phases. Shear-mediated dilation was induced by 3min of hypercapnia (target PETCO2 +10mmHg from individual baseline) and was calculated as the percent rise in peak diameter relative to baseline diameter. ICA diameter and blood velocity were simultaneously measured by Doppler ultrasound. In Pre-M, shear-mediated dilation was higher during the LF phase than during the EF phase (P<0.01). Comparing all groups, shear-mediated dilation was reduced across the menopausal transition (P<0.01), and Pre-M during the LF phase showed the highest value (8.9±1.4%) compared with other groups (Pre-M in EF, 6.4±1.1%; Peri-M, 5.5±1.3%; Post-M, 5.2±1.9%, P<0.05 for all). Shear-mediated dilation was positively correlated with serum estradiol even after adjustment of age (P<0.01, r=0.55, age-adjusted; P=0.02, r=0.35). Collectively, these data indicate that controlling the menstrual cycle phase is necessary for the cross-sectional assessments of shear-mediated dilation of the ICA in premenopausal women. Moreover, current findings suggest that a decline in cerebrovascular endothelial function may be partly related to the reduced circulating estrogen levels in peri- and postmenopausal women.

scholarly journals Both Inhibin A and B Respond to Exogenous Follicle-Stimulating Hormone in the Follicular Phase of the Human Menstrual Cycle1

1998 ◽  
Vol 83 (11) ◽  
pp. 4167-4169
Author(s):  
Henry G. Burger ◽  
Nigel P. Groome ◽  
David M. Robertson
Keyword(s):  
Menstrual Cycle ◽  
Follicle Stimulating Hormone ◽  
Follicular Phase ◽  
Serum Estradiol ◽  
Serum Samples ◽  
Control Value ◽  
Highly Correlated ◽  
Human Menstrual Cycle ◽  
Dose Dependent Increase ◽  
Dose Dependent

To ascertain whether changes in the concentrations of the dimeric inhibins A and/or B (INH-A and INH-B) contributed to the previously described dose-dependent increase in immunoreactive inhibin (INH) in response to FSH during the follicular phase of the human menstrual cycle, both dimers were measured by specific two-site assays in stored serum samples from regularly cycling normal volunteers who had received saline as a control (n = 5) or FSH [100 IU (n = 6) or 200 IU (n = 5)] between days 3–5 of the menstrual cycle. Both INH-A and INH-B showed a dose-dependent increase in response to administered FSH; INH-A rose from 13.5 to 35.9 ng/L (P &lt; 0.01), and INH-B rose from 77.8 to 205 ng/L (P &lt; 0.05) at 36 h after 200 IU FSH. Highly significant correlations were observed between INH and each of the specific inhibin dimers (A: r= 0.79, P &lt; 0.001; B: r = 0.76, P &lt; 0.001), and the responses of the two dimers were also highly correlated (r = 0.59, P &lt; 0.001). The response of each inhibin was also highly correlated with the response of serum estradiol (A: r = 0.45, P &lt; 0.001; B: r = 0.40, P&lt; 0.001). When analyzed by ANOVA, the INH response of INH-B was significantly above the control value at 36 h after treatment with both 100 and 200 IU FSH, whereas the response of INH-A was significant only at 200 IU. It is concluded that the concentrations of both dimeric INH-A and INH-B are stimulated by increases in FSH within the physiological range in the follicular phase of the human menstrual cycle and that both contribute to the previously observed rise in INH.

Effects of the menstrual cycle on mood, neurocognitive and neuroendocrine function in healthy premenopausal women

2004 ◽  
Vol 34 (1) ◽  
pp. 93-102 ◽  
Author(s):  
C. S. SYMONDS ◽  
P. GALLAGHER ◽  
J. M. THOMPSON ◽  
A. H. YOUNG
Keyword(s):  
Menstrual Cycle ◽  
Hpa Axis ◽  
Luteal Phase ◽  
Reaction Times ◽  
Premenopausal Women ◽  
Follicular Phase ◽  
Continuous Performance Task ◽  
Biological Difference ◽  
Basal Cortisol ◽  
The Relationship

Background. Neurocognitive functioning may be impaired in the luteal phase of the menstrual cycle due to associated changes in hypothalamic–pituitary–adrenal (HPA) axis function. This study examines the relationship between changes in neurocognition and HPA axis function in different phases of the menstrual cycle.Method. Fifteen female volunteers, free from psychiatric history and hormonal medication were tested twice, during mid-follicular and late-luteal phases in a randomized, crossover design. Mood, neurocognitive function, and basal cortisol and dehydroepiandrosterone (DHEA) were profiled.Results. Relative to the follicular phase, verbal fluency was impaired in the luteal phase and reaction times speeded on a continuous performance task, without affecting overall accuracy. ‘Hedonic’ scores on the UWIST-MACL scale were decreased in the luteal phase. There was also evidence of changes in the function of the HPA axis, with 24 h urinary cortisol concentrations and salivary DHEA levels being significantly lower during the luteal phase.Conclusions. These data suggest that luteal phase HPA axis function is lower than in the follicular phase in premenopausal healthy women. This putative biological difference may be important for our understanding of the aetiopathogenesis of menstrually related mood change and neurocognitive disturbance.

Subnormal follicular-phase serum progesterone levels and elevated follicular-phase serum estradiol levels in young women with insulin-dependent diabetes

Steroids ◽  
1990 ◽  
Vol 55 (12) ◽  
pp. 560-564 ◽  
Author(s):  
Barnett Zumoff ◽  
Lorraine Miller ◽  
Leonid Poretsky ◽  
Charles D. Levit ◽  
Ellen H. Miller ◽  
...  
Keyword(s):  
Young Women ◽  
Follicular Phase ◽  
Insulin Dependent Diabetes ◽  
Serum Estradiol ◽  
Serum Progesterone ◽  
Insulin Dependent ◽  
Estradiol Levels
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