scholarly journals Concentration Addition, Independent Action and Generalized Concentration Addition Models for Mixture Effect Prediction of Sex Hormone Synthesis In Vitro

PLoS ONE ◽  
2013 ◽  
Vol 8 (8) ◽  
pp. e70490 ◽  
Author(s):  
Niels Hadrup ◽  
Camilla Taxvig ◽  
Mikael Pedersen ◽  
Christine Nellemann ◽  
Ulla Hass ◽  
...  
Keyword(s):  
Sex Hormone ◽  
Concentration Addition ◽  
Independent Action ◽  
Mixture Effect ◽  
Hormone Synthesis

Mathematical Derivation of Concentration Addition, Independent Action and Effect Summation Models

2013 ◽  
Vol 361-363 ◽  
pp. 1054-1057 ◽  
Author(s):  
Hui Lin Ge ◽  
Shu Shen Liu ◽  
Bing Xia Su ◽  
Zhi Xu
Keyword(s):  
Risk Assessment ◽  
Concentration Addition ◽  
Assessment Practices ◽  
Combined Effects ◽  
Independent Action ◽  
Mixture Effect ◽  
Number Of Components ◽  
Mathematical Derivation ◽  
Mixture Risk Assessment

The assessment of the combined effects of substances is usually based on concentration addition (CA), independent action (IA) or effect summation (ES) models. Both concepts are founded on different modes of actions of substances, but the knowledge about their relationship is rare. In this paper, we derived a series of inequalities for CA, IA and ES models, and proposed two novel models i.e., ES with the exponent e (ESE) model and ES with the power of the number of components n (ESN) model to evaluate the mixture effect. Our results may have certain significance in mixture risk assessment practices.

DER EINFLUSS VON RESERPIN AUF DIE ANTITHYREOIDALE WIRKUNG VON KALIUMPERCHLORAT

1962 ◽  
Vol 39 (3) ◽  
pp. 423-430
Author(s):  
H. L. Krüskemper ◽  
F. J. Kessler ◽  
E. Steinkrüger
Keyword(s):  
Thyroid Gland ◽  
Male Rats ◽  
Normal Male ◽  
Tissue Respiration ◽  
List Type ◽  
Morphological Alterations ◽  
Hormone Synthesis ◽  
Stimulation Of

ABSTRACT 1. Reserpine does not inhibit the tissue respiration of liver in normal male rats (in vitro). 2. The decrease of tissue respiration of the liver with simultaneous morphological stimulation of the thyroid gland after long administration of reserpine is due to a minute inhibition of the hormone synthesis in the thyroid gland. 3. The morphological alterations of the thyroid in experimental hypothyroidism due to perchlorate can not be prevented with reserpine.

scholarly journals Biosynthesis of growth hormone in the rat anterior pituitary gland. Stimulation of biosynthesis in vitro by insulin

1973 ◽  
Vol 134 (4) ◽  
pp. 1103-1113 ◽  
Author(s):  
A. Betteridge ◽  
M. Wallis
Keyword(s):  
Growth Hormone ◽  
Anterior Pituitary ◽  
Rna Synthesis ◽  
Glucose Utilization ◽  
Actinomycin D ◽  
Hormone Synthesis ◽  
Pituitary Glands ◽  
Hormone Biosynthesis ◽  
Stimulation Of

The effect of insulin on the incorporation of radioactive leucine into growth hormone was investigated by using rat anterior pituitary glands incubated in vitro. A 50% stimulation over control values was observed at insulin concentrations above 2μm (280munits/ml). The effect was specific for growth hormone biosynthesis, over the range 1–5μm-insulin (140–700munits/ml). Lower more physiological concentrations had no significant effect in this system. Above 10μm (1.4 units/ml) total protein synthesis was also increased. The stimulation of growth hormone synthesis could be partially blocked by the addition of actinomycin D, suggesting that RNA synthesis was involved. Insulin was found to stimulate the rate of glucose utilization in a similar way to growth hormone synthesis. 2-Deoxyglucose and phloridzin, which both prevented insulin from stimulating glucose utilization, also prevented the effect of insulin on growth hormone synthesis. If glucose was replaced by fructose in the medium, the effect of insulin on growth hormone synthesis was decreased. We conclude that the rate of utilization of glucose may be an important step in mediating the effect of insulin on growth hormone synthesis.

Effects of calcium on synthesis and secretion of parathyroid hormone and secretory protein I

1988 ◽  
Vol 255 (3) ◽  
pp. E299-E305
Author(s):  
R. R. MacGregor ◽  
D. A. Hinton ◽  
R. D. Ridgeway
Keyword(s):  
Protein Synthesis ◽  
Steady State ◽  
Parathyroid Hormone ◽  
Total Protein ◽  
Secretory Protein ◽  
Hormone Synthesis ◽  
Synthesis And Degradation

Bovine parathyroid organoids were cultured for up to 3 wk in medium containing 1.4 or 1.8 mM calcium. Steady-state secretion of parathyroid hormone and secretory protein I was two- to fourfold greater at 1.4 mM. At the end of culture, organoids were incubated 3.5 h in 1 or 2 mM calcium to examine maximum and minimum acute secretory rates. Relative to organoids cultured at 1.8 mM calcium, culture at 1.4 mM induced a hypersecretory state, i.e., both the maximum and minimum acute secretory rates of organoids previously cultured at 1.4 mM calcium were up to threefold greater than those of organoids previously at 1.8 mM calcium. Proparathyroid hormone synthesis was up to 50% greater in organoids cultured at 1.4 mM calcium, whereas secretory protein I and total protein synthesis were unaltered. The results showed that parathyroid hypersecretion can be induced by chronic hypocalcemic conditions in vitro. We conclude that the secretory adaptation to chronic hypocalcemia in vitro involves alterations in both synthesis and degradation of parathyroid hormone.

scholarly journals Acrylamide does not induce tumorigenesis or major defects in mice in vivo

2008 ◽  
Vol 198 (2) ◽  
pp. 301-307 ◽  
Author(s):  
Ling Jin ◽  
Vanessa Chico-Galdo ◽  
Claude Massart ◽  
Christine Gervy ◽  
Viviane De Maertelaere ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Chronic Administration ◽  
Serum Levels ◽  
Human Thyroid ◽  
Thyroid Cell ◽  
Thyroid Cells ◽  
Hormone Synthesis ◽  
Rat Thyroid

Chronic administration of acrylamide has been shown to induce thyroid tumors in rat. In vitro acrylamide also causes DNA damage, as demonstrated by the comet assay, in various types of cells including human thyroid cells and lymphocytes, as well as rat thyroid cell lines. In this work, mice were administered acrylamide in their drinking water in doses comparable with those used in rats, i.e., around 3–4 mg/kg per day for mice treated 2, 6, and 8 months. Some of the mice were also treated with thyroxine (T4) to depress the activity of the thyroid. Others were treated with methimazole that inhibits thyroid hormone synthesis and consequently secretion and thus induces TSH secretion and thyroid activation. These moderate treatments were shown to have their known effect on the thyroid (e.g. thyroid hormone and thyrotropin serum levels, thyroid gland morphology…). Besides, T4 induced an important polydipsia and degenerative hypertrophy of adrenal medulla. Acrylamide exerted various discrete effects and at high doses caused peripheral neuropathy, as demonstrated by hind-leg paralysis. However, it did not induce thyroid tumorigenesis. These results show that the thyroid tumorigenic effects of acrylamide are not observed in another rodent species, the mouse, and suggest the necessity of an epidemiological study in human to conclude on a public health policy.

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