NetNews Usenet Archive 1992 #31/NN_1992_31.iso/spool/sci/med/nutritio/1731

Text File | 1993-01-02 | 7.3 KB | 162 lines

Newsgroups: sci.med.nutrition
Path: sparky!uunet!gatech!destroyer!cs.ubc.ca!newsserver.sfu.ca!sfu.ca!altar
From: [e-mail] (Ted Wayn Altar)
Subject: Re: Calcium/Magnesium
Message-ID: <[e-mail]>
Sender: [e-mail]
Organization: Simon Fraser University, Burnaby, B.C., Canada
References: <[e-mail]> <[e-mail]> <[e-mail]> <[e-mail]> <[e-mail]>
Date: Sat, 2 Jan 1993 07:53:11 GMT
Lines: 150

Craig Silver writes:


>Of the classes I attended or listened to on tape in the fall semester
>(almost all, and *all* the ones regarding calciferol) I don't remember
>Moon ever saying "anabolic steroids" when speaking of calciferol.  I
>do, however, remember his referring to calciferol as a "potent
>steroidal hormone".  I'm not even sure if this is the same thing.  But
>I thought I'd tell you what I remember hearing and what I remember not
>hearing since I was at the lectures.


With respect to "vitamin D" being an ANABOLIC SECO-STEROID
HORMONE or simply a SECO-STEROID HORMONE, this is really a silly
quibble.

That it is a seco-steroid hormone is not in doubt.  The
important point forwarded by Professor Moon, and conveyed by
yourself, is that it is indeed a steroid hormone that has some
associated risks and which is being implicated as possibly
playing a key role in some major diseases like osteoporsis and
atherosclerosis.

Still, someone interested in hasty conclusions might insist that
the use of the word "anabolic" is completely wrong and therefore
completely discredits Dr. Moon.  I most people would agree that
this is really quite rash, since even if it were the case that
Moon happens to be wrong in classifying califerol as having
anabolic effects and therefore an anabolic steroid, it still
doesn't follow that he is also completely wrong on everything
else he has said.

We might more modestly argue and say that Moon's use of the term
shows him to at least be fallible and this could cast suspicion
on the rest of his work.  Well, maybe so, but maybe Moon has good
reason to use the term as he sees fit.  After all, we ALL here
are just lay persons but Professor Moon is an accomplished expert
in the area of vitamin D.  Did someone say "No"?  Ok, may I then
ask that ALL those with published papers in a scientific medical
journal on the subject of vitamin D, please stand up!  I suspect
that nobody is standing; oops, sit down Steve!  ;-)

Now, I'm no expert on vitamin D but as far as I can understand
the term "anabolic" is not as univocal or rigidly defined in
meaning one might think.

For example, in de Gruyter's  "Concise Encyclopedia of
Biochemistry, 2nd ed., 1985", the following:

     ANABOLIC STEROIDS:  a group of synthetic steroids which
      stimulate the production of body protein.

This is referred to as the "anabolic effect" and no mention is
made that the kinds of protein have to be only those involved in
muscle tissue, although for the gonadal steroid hormones it is,
or at least that is how their anabolic effect is measured (the
so-called Hershberg test).

I had posted elsewhere the following from Anthony Norman (chpt. 6
of "Vitamin D Molecular Biology & Clinical Nutrition, edited by
Anthony Norman, 1980), who is leading expert on the biochemistry
of vitamin D.  Norman tells us that 1,25-(OH)2-vitamin D:

      has specific cells in target
      organs with specific receptor proteins; the receptor-ligand
      complex moves to the nucleus where it binds to the chromatin
      and stimulates the transcription of particular genes to
      produce specific RNAs which code for the synthesis of
      specific proteins.

What we have, then is the hormone stimulated production of
calcium binding protein, which then can result in macro skeletal
changes.  So by de Gruyter's definition as it stands, it would
seem that vitamin D can be considered as a steroid hormone having
anabolic effects, hence a anabolic steroid hormone.

In some biochemical dictionaries, the definition is even less
well-circumcribed, as in J. Stenesh, "Dictionary of
Biochemistry", 1975, where the term "anabolic" is simply defined
as "pertaining to anabolism" which in turn is defined as:

     1.  the phase of intermediary metabolism that encompasses
      the biosynthetic and energy-requiring reactions whereby cell
      components are produced.  2.  The cellular assimilation of
      macromolecules and complex substances from low-molecular
      weight precursors.

Given Norman's passage above, we again have something that
qualifies under this definition as "anabolic".  Also, there there
are dozens of articles on the stimulation of cell growth and
differentiation under the influence of calciferol.

Indeed, it seems that Anthony Norman takes it for granted that
all steroid hormones are "anabolic", with one exception:

     "there is an ever-increasing body of inferential evidence
      that suggests that ALL steroids, including 2,15-IOH)2-D3,
      act by a similar pathway to produce a similar set of general
      effects.  With the exception of the glucocorticoids, which
      produce both ANABOLIC and catabolic effects, tissue
      responses to all steroid hormones are characterized by a
      general increase in metabolism that includes RNA, DNA, and
      protein synthesis." (emphasis mine)
           (Anthony Norman, 1980 p. 210)

Now, what is this anabolic effect but none other than "a general
increase in metabolism that includes RNA, DNA, and protein
synthesis"?  The glucocortoicoids are then distinguished by their
catabolic effects, not their anabolic effects.

Now if the only argument given here on the net is merely one that
amounts to simply saying "I say so", then the expert I choose is
Professor J. Moon over that of someone, say, who has not
published anything in a scientific journal on vitamin D and only
has a BSc in biology.  Some such criterion has to be employed if
we are to decided between differing views with the information at
hand.

Also, I think we should modestly observe that scientific terms
are not rigid entities written in stone, but are evolving
concepts which are not always used in exactly the same manner by
every expert. While most if not all endrocrinologists may use the
term anabolic to refer in their practice only to the male gonadal
hormones, this does not preclude a wider usage by other experts
in other fields.

Frankly, I think this quibble is best left to the experts proper.

Our task on this conference, I think, is the more humble one
where we sincerely seek to find, understand (as best we can), and
share and report upon some interesting findings and implications
about things pertaining to nutrition.  To this end, Craig, you
properly and generously reported what you knew firsthand from
what Dr. Moon said about vitamin D in his class on nutrition.  I
did the very much the same, but my sources are different; namely,
his 2 special presentations at colloquia at SFU, 2 of his
published papers, a one page news brief in "Simon Fraser Week",
plus some direct conversations and e-mail with Dr. Moon directly.

Again, I don't presume to be infallible in my reportage, but the
kinds of criticisms we've seen so far directed to what I thought
would be an interesting report, have for the most part been
either simply unseemly personal attacks or unreferenced counter-
claims.

Oh well. :-(

                                           Ted