Effecten van oestrogeen op IGF-1 en neuroprotectieve eigenschappen.
Estrogen Regulation of Growth Hormone Action
http://edrv.endojournals.org/content/25/5/693.short
Effects of Estrogen and Sex Difference on Secretion of Human Growth Hormone
[Link niet meer beschikbaar]
Estrogen Suppression in Males: Metabolic Effects
[Link niet meer beschikbaar]
However, E2 concentrations decreased 48% (P = 0.006), with no significant change in mean and peak GH concentrations, but with an 18% decrease in plasma insulin-like growth factor I concentrations.
Estrogen Receptor α Rapidly Activates the IGF-1 Receptor Pathway
http://www.jbc.org/content/275/24/18447.abstract
Activation of estrogen receptor-mediated gene transcription by IGF-I in human breast cancer cells
[Link niet meer beschikbaar]
Neuroprotective effects of estradiol in the adult rat hippocampus: Interaction with insulin-like growth factor-I signalling
http://onlinelibrary.wiley.com/doi/1...O;2-R/abstract
Estrogen exerts neuroprotective effects via membrane estrogen receptors and rapid Akt/NOS activation
http://www.fasebj.org/content/18/13/1594.full
Neuroprotective effects of estradiol in mesencephalic dopaminergic neurons
http://www.sciencedirect.com/science...49763499000597
Neuroprotective effects of insulin-like growth factor-I (IGF-I) following a penetrating brain injury in rats
http://www.sciencedirect.com/science...0689930303525X
Neuroprotective effect of insulin-like growth factor I in immortalized hypothalamic cells.
[Link niet meer beschikbaar]
Zoals je ziet kan oestrogeen, afzonderlijk van groeihormoon, IGF-1 activeren. IGF-1 heeft dus zelf ook neuroprotectieve eigenschappen, maar vele groeifactoren hebben die eigenschap. Middelen zoals nolvadex en clomid verlagen dan ook IGF-1, ter bevestiging.
Bijkomende oorzaak kanker en oestrogeen, IGF-1?
Growth Factor Raises Cancer Risk
http://news.harvard.edu/gazette/1999/04.22/igf1.story.html
The growth factor, known as insulin-like growth factor-1, or IGF- 1, is necessary for proper growth in children, but studies of men and women more than 40 years old raise the possibility that it contributes to the growth of tumors.
Insulin-Like Growth Factor 1 and Prostate Cancer Risk: A Population-Based, CaseControl Study
http://jnci.oxfordjournals.org/content/90/12/911.short
Plasma androgens, IGF-1, body size, and prostate cancer risk: a synthetic review
http://www.ncbi.nlm.nih.gov/sites/entrez/12497092?dopt=Abstract&holding=f1000,f1000m,isrctn
Although one prospective study showed an increased risk in men with low plasma coïtus hormone-binding globulin (SHBG) and with elevated plasma T for given levels of SHBG, this was not confirmed by results from other cohort studies. A second conclusion is that overweight, which is generally associated with moderate reductions in both total and bioavailable plasma T, appears to be unrelated to any significant increase or decrease in prostate cancer risk. However, significant increases in risk have been observed for men with a taller body stature, or with elevated plasma IGF-1. IGF-1 may directly enhance prostate tumorigenesis by inhibiting apoptosis and by stimulating cell proliferation. In addition, IGF-1 downregulates the synthesis of SHBG, and enhances coïtus steroid synthesis.
Uit de onderzoeken van de
4. SHBG Inhibitors hebben we kunnen zien dat een verminderde werking of in dit geval minder SHBG de kans op prostaatkanker verhoogt.
Sommige kankers hebben ook wel oestrogeenreceptoren wat de groei kan bevorden. En onderzoek laat ook de positieve werking van anti-oestrogenen daarbij zien (ze verlagen ook IGF-1 en verhogen SHBG). Onderstaande artikel laat wel een ander licht schijnen op oestrogeen en kanker
Estrogen Reduces Breast Cancer Stem Cells and Aggression in Breast Cancer, Study Suggests
http://www.sciencedaily.com/releases/2011/02/110214083811.htm
"To our surprise, what we have seen is that estrogen reduces the proportion of breast stem cells which means a mechanism for explaining this better prognosis observed with tumors that express the estrogen receptor. That is, those tumors expressing the estrogen receptor are less aggressive, better differentiated and thus have a better prognosis," explained María Vivanco, leader of the research team.
Ms Vivanco believes that this study presents a new functional aspect of estrogen, due to its capacity for acting in a different way depending on cellular type.
We zien dus dat IGF-1 en oestrogeen (al dan niet door IGF-1 stimulatie) de kans op kanker kan verhogen en de groei verder kan stimuleren. Inhibitie van de aanmaak of werking van SHBG verhoogt dit ook weer. We hebben in onderzoek (op ratten) kunnen zien dat alleen androgenen geen prostaatkanker veroorzaakt. Pas na toevoeging van oestrogeen gebeurde er wat.
1. Aromatase Inhibitors verlagen de kans, maar hun eigen bijwerkingen (bescherming cellen die verminderd).
2. Receptor Modulators blijven de beste keuze voor test verhoging zonder de kans op kanker te verhogen. Deze verlagen de kans zelfs en beschermen tegen prostaatgroei. Red maca kan de prostaat zelfs terug verkleinen.
Vitamine D (wat je zowiezo nodig hebt voor andere functies) en soja blijven aan de top van mijn lijst staan.
