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At least 775 records · Page 43Linked to original sources
PubMed1983

The role of nonesterified fatty acids and of alpha 1-fetoprotein in estrogen-dependent endocrine systems.

We discuss the various experimental findings to date that indicate that AFP may be considered as a positive or negative modulator of estrogenic action. Moreover, we show that this protein, even when nonestrogenophilic, is able to bind other hydrophobic ligands, in particular nonesterified fatty acids. These fatty acids inhibit the binding of estrogens to murine AFP as well as to the cytosolic estrogen receptors. Thus, the AFPs of all species--whether or not estrogenophilic--might play an endocrinologic role through the intermediary of the unsaturated fatty acids to which they associate with high affinity.

Animals↗
PubMed1996

Nitric oxide synthase: role as a transmitter/mediator in the brain and endocrine system.

Nitric oxide is a unique biological messenger molecule. It is produced by endothelial cells to mediate blood vessel relaxation; it mediates, in part, the immune functions of activated macrophages; and in the central and peripheral nervous system it serves as a neurotransmitter. In the nervous system, nitric oxide may regulate neurotransmitter release, it may play a key role in synaptic plasticity and morphogenesis, and it may regulate sexual and aggressive behavior. Under conditions of excessive formation, nitric oxide is emerging as an important neurotoxin.

Aggression↗
PubMed1988

Norepinephrine effects on fetal cardiovascular and endocrine systems.

Norepinephrine (NE) was infused intravenously into near-term chronically catheterized sheep fetuses for 30 min. Infusions of 0.39, 1.2, 3.9, 12, and 39 micrograms/min caused a 1- to 300-fold increase in plasma NE concentration. Fetal arterial pressure increased in a dose-dependent manner up to a maximum of 72 +/- 5% above basal levels at 6-7 min and gradually declined thereafter. Venous pressure increased during the four highest infusion rates to a maximum at 6-7 min followed by a return toward normal. Fetal blood volume underwent a rapid dose-dependent decrease by a maximum of 12 +/- 1% during 39-micrograms/min infusions of NE. Heart rate initially decreased by up to 40 beats/min during the 3.9-, 12-, and 39-micrograms/min infusions, returned to normal within 10 min, and increased to 50 beats/min above control by the end of the 30-min infusion. Plasma concentrations of arginine vasopressin, epinephrine, and plasma renin activity did not change during or after the four lowest infusion rates. Thus fetal vascular pressures and blood volume are altered in a dose-dependent manner over a broad range of plasma NE concentrations. In addition, NE does not appear to affect other circulating vasoactive hormones within its physiological range of concentrations.

Animals↗
PubMed2006

Critical appraisal of primary systemic endocrine therapy in receptor-positive postmenopausal breast cancer: an update.

Even in elderly patients, greater consideration is now being given to tumor volume reduction in locally advanced breast cancer, with increased subsequent breast-conserving surgery. Neoadjuvant endocrine therapy offers the possibility of testing therapeutic efficacy in vivo, which is of great importance for optimal adjuvant treatment. Resulting therapy modifications can be expected to increase disease-free as well as overall survival. Recent results indicate that remission rates with primary chemotherapy are significantly lower in receptor-positive than in receptor-negative breast cancer and that efficacy parameters in receptor-positive tumors tend to favor primary endocrine therapy, highlighting the increased importance of this type of treatment. Aromatase inhibitors are superior to tamoxifen in terms of clinical response as well as breast conservation rate. Results from a small number of studies suggest that prolonged preoperative aromatase inhibitor therapy for up to 12 months can increase the rate of clinical and pathological complete remissions. In conclusion, primary endocrine therapy is a valid therapeutic option for postmenopausal patients with locally advanced hormone receptor-positive breast cancer and significant comorbidity, increased risk of complications with regard to anesthesia and surgery, desire for breast-conserving surgery and/or reduced suitability for chemotherapy, as well as in very old patients.

Aromatase Inhibitors↗
PubMed1988

Serum bone gla protein and the vitamin D endocrine system in the oophorectomized rat.

Because of the importance of estrogen in osteoporosis, the effects of decreased estrogen production using sensitive measurements of bone mineral metabolism were studied in oophorectomized rats. Serum levels of ionized calcium, bone gla protein (BGP), vitamin D metabolites (25-hydroxyvitamin D and 1,25-dihydroxyvitamin D), and estradiol were measured before and serially for 6 weeks after oophorectomy in the rat. In addition, static and dynamic indices of bone histomorphometry were determined after double tetracycline labeling. Fifty Sprague-Dawley female rats (approximately 250 g) were studied. Twenty-five rats underwent oophorectomy (O), while the remaining rats were sham operated. Estrogen deficiency was noted in the O group within a week after surgery (estradiol, 2.45 +/- 0.78 vs. 27.9 +/- 4.15 pg/ml; P less than 0.05). Serum ionized calcium levels, 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, and PTH levels did not differ between the two groups during the length of the study. Serum BGP levels were the same in both groups until the second week postoophorectomy, after which BGP remained significantly elevated in the O animals (121.7 +/- 5.95 vs. 76.7 +/- 3.87; P less than 0.001). Bone histomorphometry revealed increased osteoid volume (4.4 +/- 0.9% vs. 2.3 +/- 0.7%), osteoblast surface (26.5 +/- 2.4% vs. 3.2 +/- 1.2%), tetracycline surface (18.9 +/- 4.1% vs. 6.8 +/- 2.2%), as well as osteoclast surface (8.2 +/- 1.4% vs. 2.5 +/- 2%) in all O animals compared with those in the sham-operated group. These data indicate that oophorectomy and decreased estrogen result in increased bone turnover with elevated BGP levels. The marked BGP elevation within 2 weeks postoophorectomy suggests that estrogen withdrawal results in rapid altered bone mineral metabolism. The lack of concomitant increase in circulating PTH levels suggests that other factors may be mediating the bone loss following surgical oophorectomy.

Animals↗
PubMed1997

Angiotensin-converting enzyme gene polymorphism and cardiovascular endocrine system in coronary angiography patients.

There is continuing interest in the link between angiotensin-converting enzyme (ACE) insertion/deletion (I/D) polymorphism and cardiovascular diseases. Studies on various ethnic populations have shown conflicting evidence as to the association of the DD genotype with an increased risk of myocardial infarction. We examined the relationship between various cardiovascular hormones and ACE gene polymorphism in 149 subjects who underwent cardiac catheterization and had normal cardiac function. The distribution of the II, ID, and DD genotypes was 68, 67, and 14, respectively. Although serum ACE activity was higher in DD and ID than in II (II 9.7+/-0.5 IU/l, ID 12.2+/-0.5, DD 12.8+/-1.2; p < 0.005), other factors of the renin-angiotensin system such as plasma renin activity and plasma concentrations of angiotensin II and aldosterone were not different among the three genotypes. Plasma catecholamines did not differ among the ACE genotypes either, however, plasma atrial natriuretic peptide (ANP) was significantly lower in the subjects carrying the D allele (II 38+/-5 pg/ml, ID 26+/-2, DD 21+/-3; p < 0.05). In particular, the DD genotype showed a low plasma ANP level although the left ventricular mass index was greater than the other genotypes (II 133+/-5 g/m2, ID 137+/-6, DD 165+/-7; p < 0.05). The low plasma ANP in the DD genotype may contribute to the increased risk of cardiovascular diseases.

Atrial Natriuretic Factor↗