In article <ralph.1141727083A at news.arizona.edu>,
Ralph M Bernstein <ralph at ccit.arizona.edu> wrote:
>Ok, re re re the taxonomy question.....
>>prev written in response to my posting:
>>>>>This is not true at all. While steroid hormones are membrane soluble and
>>act on receptors that are transcription factors, the peptide hormones
>>(growth hormone, ACTH, insulin) and amino acid derivatives (serotonin,
>>dopamine, epinephrine) all work through membrane-bound receptors.
>>what is not true at all? there is obviously a diff between steroid and
>peptide hormones, but what i said obviously holds true for steroid hormones.
The implication in your post was that *all* hormones are lipid soluble and
bind to transcription-factor receptors, and that this was a difference
between hormones and cytokines. I simply was pointing out that there are
classes of hormones that are similar enough to cytokines to group them
together.
>is this the role of a hormone, is the
>release of a messanger from a non-"organ" the only defining factor?
> let me hear you input into this.
I'm not sure I understand the question. Many hormones are released from
"organs" (pituitary gland, adrenal gland, etc.). I found a pretty good
definition for hormones in "Basic Medical Endocrinology" by H. Maurice
Goodman: "a chemical substance that is released into the blood in small
amounts and that, after delivery by the circulation, elicits a typical
physiological response in other cells." This would include the classical
"hormones", as well as cytokines, growth factors, hormone releasing factors,
arachidonic acid derivatives, etc.
BioKen
--
Ken Frauwirth (MiSTie #33025) _ _
frauwirt at mendel.berkeley.edu |_) * |/ (_ |\ |
Dept. of Molec. & Cell Bio. |_) | () |\ (_ | \|
Univ. of Cal., Berkeley Push the button...someone :(
