The agonistic bioanalytical equivalent concentration: A novel tool for assessing the endocrine activity of environmental mixtures

2022 ◽  
Vol 89 ◽  
pp. 103781
Author(s):  
Martin Ezechiáš
Keyword(s):  
Endocrine Activity ◽  
Equivalent Concentration ◽  
Environmental Mixtures

Ultrastructural morphology of nontumorous lactotrophs in human pituitaries exposed to high prolactin levels

1987 ◽  
Vol 45 ◽  
pp. 896-897
Author(s):  
S. Jalalah ◽  
K. Kovacs ◽  
E. Horvath
Keyword(s):  
Anterior Pituitary ◽  
Secretory Activity ◽  
Pituitary Hormones ◽  
Feedback Mechanism ◽  
Endocrine Activity ◽  
Hormone Synthesis ◽  
Anterior Pituitary Hormones ◽  
Negative Feedback Mechanism ◽  
Ultrastructural Morphology ◽  
Transmission Electron

Lactotrophs, as many other endocrine cells, change their morphology in response to factors influencing their secretory activity. Secretion of prolactin (PRL) from lactotrophs, like that of other anterior pituitary hormones, is under the control of the hypothalamus. Unlike most anterior pituitary hormones, PRL has no apparent target gland which could modulate the endocrine activity of lactotrophs. It is generally agreed that PRL regulates its own release from lactotrophs via the short loop negative feedback mechanism exerted at the level of the hypothalamus or the pituitary. Accordingly, ultrastructural morphology of lactotrophs is not constant; it is changing in response to high PRL levels showing signs of suppressed hormone synthesis and secretion.By transmission electron microscopy and morphometry, we have studied the morphology of lactotrophs in nontumorous (NT) portions of 7 human pituitaries containing PRL-secreting adenoma; these lactotrophs were exposed to abnormally high PRL levels.

ENDOCRINE ACTIVITY OF THE HUMAN FALLOPIAN TUBE

1969 ◽  
Vol 61 (1_Suppl) ◽  
pp. S80 ◽  
Author(s):  
Hubertus A. van Leusden
Keyword(s):  
Fallopian Tube ◽  
Endocrine Activity ◽  
Human Fallopian Tube

The existence during gestation of an immunological buffer zone at the interface between maternal and foetal tissues

1975 ◽  
Vol 271 (912) ◽  
pp. 343-361 ◽  
Keyword(s):  
Buffer Zone ◽  
Placental Lactogen ◽  
Apical Plasma Membrane ◽  
Hormonal Changes ◽  
Endocrine Activity ◽  
Maternal Tissue ◽  
Local Survival ◽  
Receptor Sites ◽  
Probable Interaction ◽  
Immunological Attack

In mammalian pregnancy the trophoblast normally constitutes an uninterrupted boundary of foetal tissue in immediate contact with maternal tissue, including blood in some species, and is the decisive immunological barrier to rejection of the foetus as an allograft. The ability of the trophoblast to function as a barrier evidently results from its capacity to resist immunological attack by either alloantibody or alloimmune cells and to prevent immunocompetent cells from reaching and damaging the foetus but, as yet, there is no general agreement regarding the means by which it exercises these functions. In view of the dramatic hormonal changes that occur during pregnancy and the undisputed involvement of trophoblast in these endocrine events, the possibility exists of an interaction between the hormones of pregnancy and the immunological phenomena. The present account furnishes evidence that endocrine activity at the maternal surface of the trophoblast, the presumptive site of the immunological frontier between foetus and mother, may be a factor in its local survival at implantation. The placental hormones so far known that are capable of blocking the antigen receptor sites of the mother’s lymphocytes and thus preventing the latter from reacting with the foetal antigens are the glycoprotein, human chorionic gonadotrophin (HCG) and the polypeptide hormone, human chorionic somatomammotrophin (HCS) or human placental lactogen (HPL), both of which are specific to the human placenta. The origin of these hormones, their spatial distribution and their probable interaction with placental steroid hormones are discussed. It is argued that the place of highest concentration of these hormones is on the surface of the syncytial microvilli and the adjacent caviolae of the apical plasma membrane, as well as on the surfaces of the persisting cytotrophoblastic cells of the basal plate (cytotrophoblastic shell), the cell islands and the septa - precisely where the immunological challenge of the foetal allograft to the maternal host occurs. An explanation is offered for the continuing production of the voluminous quantities of these hormones during human pregnancy.

De Novo Development of a Cavernous Malformation of the Brain: Significance of Factors with Paracrine and Endocrine Activity: Case Report

Neurosurgery ◽  
2002 ◽  
Vol 50 (3) ◽  
pp. 646-650 ◽  
Author(s):  
Wolf Lüdemann ◽  
Verena Ellerkamp ◽  
Alexandru C. Stan ◽  
Sami Hussein
Keyword(s):  
Case Report ◽  
De Novo ◽  
Cavernous Malformation ◽  
Endocrine Activity ◽  
The Brain

scholarly journals Ethylene Oxide Exposure in U.S. Populations Residing Near Sterilization and Other Industrial Facilities: Context Based on Endogenous and Total Equivalent Concentration Exposures

2021 ◽  
Vol 18 (2) ◽  
pp. 607
Author(s):  
Patrick J. Sheehan ◽  
Ryan C. Lewis ◽  
Christopher R. Kirman ◽  
Heather N. Watson ◽  
Eric D. Winegar ◽  
...  
Keyword(s):  
Cancer Risk ◽  
Ethylene Oxide ◽  
Environmental Protection Agency ◽  
Cancer Risk Assessment ◽  
Exposure Concentration ◽  
Increase Cancer Risk ◽  
Total Exposure ◽  
Industrial Facilities ◽  
Equivalent Concentration ◽  
Current Risk

Given ubiquitous human exposure to ethylene oxide (EO), regardless of occupation or geography, the current risk-specific concentrations (RSCs: 0.0001–0.01 ppb) from the U.S. Environmental Protection Agency (EPA) cancer risk assessment for EO are not useful metrics for managing EO exposures to the general U.S. population. The magnitude of the RSCs for EO are so low, relative to typical endogenous equivalent metabolic concentrations (1.1–5.5 ppb) that contribute ~93% of total exposure, that the RSCs provide little utility in identifying excess environmental exposures that might increase cancer risk. EO monitoring data collected in the vicinity of eight EO-emitting facilities and corresponding background locations were used to characterize potential excess exogenous concentrations. Both 50th and 90th percentile exogenous exposure concentrations were combined with the 50th percentile endogenous exposure concentration for the nonsmoking population, and then compared to percentiles of total equivalent concentration for this population. No potential total exposure concentration for these local populations exceeded the normal total equivalent concentration 95th percentile, indicating that excess facility-related exposures are unlikely to require additional management to protect public health.

scholarly journals Changes in Brain Monoamines Underlie Behavioural Disruptions after Zebrafish Diet Exposure to Polycyclic Aromatic Hydrocarbons Environmental Mixtures

2017 ◽  
Vol 18 (3) ◽  
pp. 560 ◽  
Author(s):  
Caroline Vignet ◽  
Verena Trenkel ◽  
Annick Vouillarmet ◽  
Giampiero Bricca ◽  
Marie-Laure Bégout ◽  
...  
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Brain Monoamines ◽  
Polycyclic Aromatic ◽  
Environmental Mixtures ◽  
Diet Exposure

Activation of two environmental mixtures by plant S9

1989 ◽  
Vol 222 (1) ◽  
pp. 9-18 ◽  
Author(s):  
Barbara S. Shane ◽  
Ann L. Looney
Keyword(s):  
Environmental Mixtures
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