Dear Robin,
There has been plenty of evidence for insulin to decrease SHBG and increase
testosterone. Both free and total testosterone increase, the latter by the
effects of insulin on stroma/theca cells, with LH acting
synergistically. It is also well-known that PCOS patients who lose weight,
thereby bringing their insulin levels down, get an increase in SHBG, lower
their free testosterone and improve their reproductive hormonal
balance. The following article is a recent one on the interesting issue
that you have raised. However, it is worth mentioning that the insulin
insensitivity in PCOS seems to have some different characteristics to that
secondary to obesity.
With best wishes,
Reza
J Clin Endocrinol Metab 2003; 88: 1528-33
The biological variation of testosterone and sex hormone-binding globulin
(SHBG) in polycystic ovarian syndrome: implications for SHBG as a surrogate
marker of insulin resistance
Jayagopal V, Kilpatrick ES, Jennings PE, Hepburn DA, Atkin SL.
J Clin Endocrinol Metab 2002; 87: 5821-5
Prediction of insulin sensitivity in nonobese women with polycystic ovary
syndrome
Cibula D, Skrha J, Hill M, Fanta M, Haakova L, VrbIkova J, Zivny J.
At 12:25 29/07/03, Robin Marks wrote:
>Hello there !
>I am no expert on these matters but I have a feeling that SHBG levels are
>more significant than is generally recognised.
>
>For example here is a snippet:
>
>Arch Gynecol Obstet. 2003 Jun;268(2):107-12. Epub 2002 Sep 26.
>The comparison of clinical and hormonal parameters in PCOS patients
>treated with metformin and GnRH analogue. Cicek MN, Bala A, Celik C,
>Akyurek C. Faculty of Medicine, Department of Obstetrics and Gynecology,
>Selcuk University, Akyokus 42080 Konya, Turkey.
>
>... Metformin treatment resulted in a significant decline in mean body
>mass index, body weight, circumferences of waist and hip and total
>hirsutismus score. There was a significant decrease in luteinizing hormone
>(LH) levels and a significant increase in follicle stimulating hormone (FSH),
>progesterone, and sex hormone binding globulin (SHBG) concentrations...
>
>Thus although SHBG increased and 'hirsutismus score' improved, it appears
>(because it is not mentioned) that there was no significant change in
>testosterone/'random number'.
>
>Does anybody think that hirsutism/acne/PCOS etc. may be more clearly
>related to SHBG than to testosterone/DHAS/androstenedione etc. ?
>
>Dr Robin Marks
>Consultant Chemical Pathologist
>Calderdale Royal Hospital
>Halifax
>HX3 0PW
>UK
>
> > -----Original Message-----
> > From: JG MIDDLE [mailto:[log in to unmask]]
> > Sent: 28 July 2003 14:10
> > To: [log in to unmask]
> > Subject: Testosterone assays better than guessing?
> >
> >
> > Listmembers who have agonised over which testosterone assay
> > to use in women should be aware that a random number
> > generator may be just as useful!
> >
> > The latest edition of Clinical Chemistry includes an article
> > describing a major comparison study of commercial
> > immunoassays with ID-GCMS (the reference method), and an
> > Editorial deploring the current state-of-the-art of
> > testosterone assays.
> >
> > Go here for links
> > http://www.ukneqas.org.uk/saf01.htm
> >
> > To those who have followed the UK NEQAS ID-GCMS exercises
> > over the years (you can download a pdf of the latest one for
> > testosterone from the SAF link), these findings will come as
> > no surprise.
> >
> > A major collaborative effort between laboratory, clinical and
> > industry personnel is needed to address this issue.
> >
> > Useful discussions were had at the UK NEQAS SAF meeting last
> > December; more concerted action is needed now.
> >
> > Jonathan Middle
> >
> >
> >
> > UK NEQAS Birmingham
> > tel 0121 414 7300, fax 0121 414 1179
> > This message is intended only for the above named
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> > represent those of UK NEQAS Birmingham, the UK NEQAS
> > Organisation, the University Hospital Birmingham NHS Trust or
> > University of Birmingham.
> >
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