On 5/9/02 11:13 AM, "Automatic digest processor"
<[log in to unmask]> wrote:

> Laurie asks when you can tell that endocrine control of milk synthesis has
> been taken over by autocrine control.  In my clinical observations I used
> to say it was around 6 to 8 weeks, when the breasts stopped feeling full
> before every feed, responding more closely to the infant's needs.  This
> also seemed to correlate with the published data for when the falling
> prolactin levels reached near baseline.
> HOWEVER, in my discussions with Prof Peter Hartmann he feels that as soon
> as the initial endocrine melee which occurs at birth has happened and
> caused Lactogenesis II then autocrine control begins.  I can see the
> scientific rationale here.
> Prolactin, while we know that it doesn't control milk synthesis, is very
> important for the production of breastmilk ... those levels still being
> high seem to have an effect (in my clinical experience) on milk production.
> What are others thoughts on the science and the art of this part of lactation?

I have to agree that autocrine control kicks in very quickly after (or at
the time of) the initiation of Lactogenesis II, however may not be "finely
tuned" (or the results of the contro lmay not be seen) until some weeks
later. Just a comment about prolactin - as we learn more, I think its
beginning to become more important to differentiate between serum prolactin
and milk prolactin. Certainly there seems to be  no association between milk
production volumes and serum prolacin (ie we say serum prolactin is
permissive for lactation) however the level of milk prolactin in the
lactocyte does appear to be associated and may possibly be a component of
the autocrine control (along with FIL, fatty acids and change in morphology
of the lactocyte as it fills and empties). There is however no association
been shown at this time between serum prolactin and changes in milk
prolactin levels. Lots more to research!!!

Cathy Fetherston
Perth, Western Australia

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