Estrogen – Women & GHRH/GHRP-6

Estrogen – Women & GHRH/GHRP-6


Well, DHEA conversion to estrogen has a pronounced positive effect on GH.

But I wonder…if you have a big fat pad & are an older guy or even a younger guy with a hormonal profile skewed toward “excess” estrogen already…whether DHEA will have a positive impact on GH production.

Conversely what happens when we reduce either estrogen or its ability to act…

AND which is more important in regard to the negative impact on GH:

  • the act of aromatization of testosterone to estradiol or
  • absolute estrogen levels

Well, that study I posted in post #492 found that the aromatization of testosterone to estradiol was important and that tamoxifen at 20 mg/day for 3 weeks reduced GH by about 50%, GH pulse by about 40% and IGF-1 by about 30%.

How about estrogen in general? … let us look at estrogen supplementation (in females)

Well, estrogen impairs the action of GH. Women are less responsive than men to GH treatment.

Oral estrogen especially inhibits GH’s actions in a dose-dependent fashion. However transdermal estrogen administration seems to bypass some of the increases in body fat and reductions in lean mass often seen in postmenopausal women given oral estrogen….so that mode of administration appears to minimize some of the negative impacts of GH.

Oral estrogen administration leads to a reduction in IGF-I levels despite an increase in GH levels (from supplementation). The reason being that estrogen impairs the ability of GH to stimulate hepatic IGF-I production because of its negative impact on the growth hormone receptor and signalling.

Estrogen inhibits GH activation of the JAK/STAT pathway. The inhibition is dose-dependent and results from suppression of GH-induced JAK2 phosphorylation, leading to a reduction in transcriptional activity. Estrogen does not affect phosphatase activity but stimulates expression of SOCS-2, which in turn inhibits JAK2 activation. Thus, estrogen inhibits GH receptor signalling by stimulating SOCS-2 expression. – Growth hormone receptor modulators, Vita Birzniece & Akira Sata & Ken KY Ho, Rev Endocr Metab Disord So how does estrogen affect the use of GHRH and GHRP-6 to effect release of GH?

It seems that GHRP-6 (assume all GHRPs) induce a greater GH release response in the somatotrophs in the presence of estrogen then GHRH. Estrogen administration markedly decreases GH release in response to GHRH. *

So women should always include a GHRP (GHRP-6, GHRP-2, Hexarelin, Ipamorelin) in their therapy. GHRH (mod GRF(1-29), Sermorelin, CJC-1295) by itself will be inhibited in its action on GH release by the sex hormone estrogen.

  • – Regulation of His-dTrp-Ala-Trp-dPhe-Lys-NH2 (GHRP-6)-induced GH Secretion in the Rat, Federico Malloa, Neuroendocrinology 1993;57:247-256

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