TurtleTank
Member
Hey guys,
I know this subject has come up quite a bit, but I couldn’t find a definitive answer from our resident geniuses.
When I look up research papers, the Tamoxifen effect on IGF is well documented, though the cause is always speculative.
However, all the speculation I find is that estrogen plays a role in the signaling of GHRH to release GH. Example:
“Estrogens appear to play a permissive role in growth hormone (GH) release by the pituitary gland and GH is known to stimulate IGF-I expression by hepatocytes. It is therefore possible that blockade of estrogen receptors in the hypothalamic-pituitary axis by tamoxifen interferes with GH release, leading to reduced hepatic IGF-I expression.” Tamoxifen reduces serum insulin-like growth factor I (IGF-I) - Breast Cancer Research and Treatment
Another:
“Our study confirm the inhibitory effect of tamoxifen on IGF-I and suggested, as shown in previous in vitro data, that its suppression could be directly related to GH reduction in response to GHRH stimulation.”
pubmed.ncbi.nlm.nih.gov
If that is the case, wouldn’t exogenous administration of GH negate the impact on IGF and effectively eliminate this as an issue for bodybuilders taking GH?
I know this subject has come up quite a bit, but I couldn’t find a definitive answer from our resident geniuses.
When I look up research papers, the Tamoxifen effect on IGF is well documented, though the cause is always speculative.
However, all the speculation I find is that estrogen plays a role in the signaling of GHRH to release GH. Example:
“Estrogens appear to play a permissive role in growth hormone (GH) release by the pituitary gland and GH is known to stimulate IGF-I expression by hepatocytes. It is therefore possible that blockade of estrogen receptors in the hypothalamic-pituitary axis by tamoxifen interferes with GH release, leading to reduced hepatic IGF-I expression.” Tamoxifen reduces serum insulin-like growth factor I (IGF-I) - Breast Cancer Research and Treatment
Another:
“Our study confirm the inhibitory effect of tamoxifen on IGF-I and suggested, as shown in previous in vitro data, that its suppression could be directly related to GH reduction in response to GHRH stimulation.”
Effect of tamoxifen on GH and IGF-1 serum level in stage I-II breast cancer patients - PubMed
Our study confirm the inhibitory effect of tamoxifen on IGF-I and suggested, as shown in previous in vitro data, that its suppression could be directly related to GH reduction in response to GHRH stimulation.
pubmed.ncbi.nlm.nih.gov
If that is the case, wouldn’t exogenous administration of GH negate the impact on IGF and effectively eliminate this as an issue for bodybuilders taking GH?
