Cortisol vs. corticosterone

Theophilus Samuels theophilus.samuels at btinternet.com
Wed Apr 19 17:47:27 EST 2000


  Cortisol is the predominant glucocorticoid in humans (and is produced in
the renal zona fasciculata), whereas corticosterone is less abundant in
humans, but is the dominant glucocorticoid in rodents (in humans it is
produced in the zonae fasciculata AND glomerulusa). Perhaps one of the most
crucial differences between these two compounds, is that corticosterone is
the precursor molecule to the mineralocorticoid aldosterone, one of the
major homeostatic modulators of sodium and potassium levels in vivo. The
enzyme 11beta-hydroxylase acts on two different molecules to give rise to
either cortisol or corticosterone (note that this enzyme is also a
mitochondrial enzyme).
  As soon as steroid hormones are made in the adrenal glands they are almost
immediately released into the plasma, so very little storage takes place.
Cortisol of course, responds to the release of ACTH and is its most
important stimulus, therefore factors that regulate ACTH release also affect
cortisol release and include stress, a negative feedback control and the
diurnal rhythm of secretion. In respone to ACTH, the main compound formed is
cortisol. Remember that corticosterone belongs to the pathway that
ultimately produces aldosterone, and therefore its regulation is almost
completely different (the primary regulators are the Renin-Angiotensin
system) and is therefore not greatly affected by the secretion of ACTH.
  The negative feedback loop involved in the production of CRH does not
involve corticosterone, only cortisol (unless this has changed in the past
few years! - check the latest reseaarch). Therefore an increase in
[corticosterone] should not affect the [CRH].
  Cortisol and corticosterone are glucocorticoids and have potent
anti-inflammatory properties, whereas actual corticosteroids (i.e.
prednisolone) possess immunosuppressant properties and are therefore the
drugs of first choice in preventing organ transplant rejection (and in high
doses to prevent rejection episodes) in the clinic. Are you sure you meant
to question their immunosuppressive qualities?

  T.L.S.





Russell Farris <tryggvi at email.msn.com> wrote in message
news:eBr87ehq$GA.303 at cpmsnbbsa04...
> What is the difference between cortisol and corticosterone? In animal
> studies, I see corticosterone mentioned where I would expect cortisol to
be
> mentioned in human studies.
>
> Are both produced in response to ACTH?
>
> Are their immunosuppressive qualities similar?
>
> Does an increase in corticosterone reduce the production of CRH by the
> hypothalamus?
>
> Thanks.
>
> Russ Farris
>
>






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