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It is interesting to see for the first time that some men do not have increases in estradiol after a shot of testosterone. 9 out of 21 were in this group. They are also the ones with lower T peak values.
I have not read the whole paper to see what estradiol test they used and if there is something in those 9 men that differentiates them from the rest at baseline.
Effect of a single injection of testosterone enanthate on 17? estradiol and bone turnover markers in hypogonadal male patients.
Camozzi V, et al
J Endocrinol Invest. 2014 Oct 16.
Abstract
Purpose
Several clinical studies testify the critical role played by estrogens in male bone metabolism. The aim of our study is to assess the effect of a single injection of testosterone enanthate in a group of hypogonadal men on 17? estradiol serum levels and some bone metabolic parameters.
Method
Twenty-one hypogonadal males were given one testosterone enanthate injection (250 mg). Blood samples were drawn before the injection and after 1, 2 and 3 weeks. The following variables were measured: Total testosterone (TT), 17? estradiol (17? E2), Sex hormone binding globulin, total alkaline phosphatase, osteocalcin, and C-telopeptide of type I collagen (CTx).
Results
After testosterone injection, both TT and 17? E2 increased, peaking 1 week after the injection. Individual observation of the response of 17? E2 to testosterone showed that a subgroup (n = 9) failed to respond with any increase in 17? E2 at any of the weekly tests (group E2-), while the remainder (n = 12) showed a significant increase in 17? E2, which reached a mean value three times higher than at baseline (group E2+).The E2- patients reached a TT peak lower than that observed in the E+ group. CTx serum levels declined progressively in the E2+ group, reaching the significance (p = 0.03) at the end of the study, while it did not change in E- group.
Conclusion
This study suggests that a single injection of testosterone might have different effects on the production of endogenous estrogens, and a significant reduction of bone resorption parameters takes place only in the patients who show a significant increase of 17ß estradiol in response to testosterone administration.
