I remember reading some old studies years ago that reported interaction between the vitamin D receptor [VDR] & the androgen receptor [AR]. Implying that one must have sufficient (hormonal) vitamin D & androgen to get the effect. From 2003 [2]:
"Male Sprague-Dawley rats (165 days old) were either kept intact or castrated. Seven days after castration, the rats were treated with vehicle (control) or 1,25 D for 3 weeks and then sacrificed. ... Administration of 1,25 D in the intact animals decreased the prostatic size by 40%, compared to control animals, whereas 1,25 D did not influence the size of the prostate in castrated rats. 1,25 D administration in intact groups also increased both the AR and VDR protein levels by approximately twofold, whereas in castrated groups, 1,25 D only increased the AR protein level by 1.5-2.5-fold. 1,25 D in the presence of endogenous testosterone inhibits prostatic growth, whereas 1,25 D in the absence of endogenous testosterone does not affect prostatic growth. The growth inhibitory activity of 1,25 D in the presence of testosterone may be mediated through the ligand activated AR and VDR pathways."
Note "1,25 D" is hormonal vitamin D.
The Abstract of the new study requires many more clarification notes, but the last sentence is clear enough:
"... supplementation of vitamin D3 and testosterone can restrict the energy production that is required to drive PCa progression by maintaining proper zinc homeostasis and inhibiting TCA cycle activity in PCa cells."
Note "TCA cycle" is the tricarboxylic acid cycle, better known as the Krebs cycle (& also as the citric acid cycle).
This may help explain why loss of the ability to convert circulating 25-D to 1,25-D is an early event in PCa.
If you have read this far, you will be wondering if vitamin D is useful while on ADT. With castrate testosterone [T], the joint regulatory role of the VDR & AR cannot occur, but there might be other roles.
For men not on ADT who are supplementing with vitamin D, the studies point to the importance of maintaining adequate T.
Googling for T range, I get this on the first page:
"normal testosterone levels range from 240 to 950 nanograms per deciliter (ng/dL)"
"normal range in males is about 270 to 1070 ng/dL with an average level of 679 ng/dL"
"testosterone levels for healthy men is within 300 – 1,110 ng/dL"
"The harmonized normal range for testosterone in a non-obese population of European and American Men, 19-39 years, is 264-916 ng/dL."
Crazy that such wide ranges would be classed as "normal".
The modern cut-off for hypogonadism appears to be 350 ng/dL, so I'd have to call that level "adequate". (In the sense that vitamin C is adequate when you don't have scurvy.)
Morgentaler puts androgen receptor saturation much lower (100 points or more lower).
To be safe & free of the dangers of estrogen dominance, I'd say one should be above 700 ng/dL.
Another answer: whatever you were at when age 21. LOL
I'm 74 the VA says my T is normal at 200 for my age. I disagreed with them I said it should be higher. Last PSA 20.45. I ask for some additional blood work which they refused. More on the lines of estrogen levels. It's more like the VA is only interested in Slice and Dice. I did the bone MRI report looks great. Did the prostrate MRI yesterday waiting on results.
About 2 months ago I started D3 K2 liquid, Nacent Iodine, BIRM along with other vitamins.
I had a biopsy that,came back with low grade PCa about 5 years ago. Watch and wait.
Read this write up shouldn't my T level be higher?
In my view, a T of 200 should normally be treated, even if there are no symptoms of hypogonadism. But does your PCa diagnosis make that unwise? See [1] for a modern view of the issue.
I hate to sound dumb but my urologist doesn't offer up any answers to any of my concerns or questions. I have requested the VA to send me to a civilian Urologist. Maybe I can get straight answers.
Thank you for the link and taking the time to reply.
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