Could your Femur be Talking to Your Brain?? Bone as an Endocrine Organ
Could your femur be helping to tell your brain when you’ve eaten enough?
It sounds slightly ridiculous.
Most of us were taught to think of bones as the framework underneath everything else.
They hold us upright. They protect our organs. They give our muscles something to pull against.
But bone as an endocrine organ gives us a very different picture of the skeleton.
Bone is living, responsive tissue.
It senses loading, adapts to demand and produces chemical messengers that communicate with other parts of the body.
Your skeleton is far from silent.
What might your femur know about lunch?
One particularly intriguing messenger is called lipocalin-2.
Lipocalin-2 is produced in several tissues in the body, but researchers have discovered that osteoblasts, the cells involved in building bone, are also an important source.
Animal studies suggest that bone-derived lipocalin-2 can communicate with areas of the brain involved in appetite and influence food intake.
Further research has found interesting effects in primates and associations in humans, although scientists are still establishing precisely how significant this pathway is for us.
So we cannot yet say that your femur decides when you should put down your fork.
But we can say that bone may participate in the conversation that helps regulate appetite and energy balance.
That is rather different from seeing the skeleton as a passive collection of supporting structures.
Your bones are also talking to your kidneys
Lipocalin-2 isn’t the skeleton’s only surprising messenger.
Bone cells also produce FGF23, a hormone that communicates primarily with the kidneys.
FGF23 helps regulate how the kidneys handle phosphate and influences the activation and breakdown of vitamin D.
This bone-to-kidney relationship is a well-established part of human physiology.
Think about that for a moment.
Cells buried within your skeleton release a hormone that travels through the circulation and gives instructions to your kidneys.
Bone isn’t merely supporting the rest of the body.
It is participating in its regulation.
Why bone as an endocrine organ matters to therapists
This doesn’t mean that a hands-on therapist should attempt to “treat” lipocalin-2, FGF23 or any other hormone.
It means that our picture of the body may be far too limited if we think only in terms of individual muscles, joints and areas of tight fascia.
When we find a painful or restricted area, it is tempting to think:
There is the problem. I need to release it.
But what if that restriction is part of a much larger adaptation?
Bone responds to the way it is loaded.
Muscles respond to the work they are being asked to do.
Fascia adapts to movement, pressure and repeated patterns.
The nervous system continually assesses whether movement feels safe.
None of these systems works alone.
If a client arrives with tension around the hip or thigh, we might ask:
Has the way they walk or load that leg changed?
Are they protecting a previous injury?
Have they become less active?
Has the foot changed what is happening higher up the limb?
Is the pelvis or opposite side altering the demands placed upon the femur?
Have there been wider changes in their health, medication, nutrition, hormones or recovery?
Is something in their history suggesting that medical assessment or referral would be appropriate?
These questions don’t provide us with one neat explanation.
They stop us from settling too quickly for one.
The restriction may not be the problem
A tight area isn’t always something that has simply forgotten how to relax.
Sometimes it is working hard because something else isn’t contributing effectively.
Sometimes it is helping the person feel stable.
Sometimes it is responding to an old injury, a change in loading or a protective strategy that has outlived the original problem.
Before attempting to release it, we could ask:
What is this tissue responding to?
What responsibility has it been carrying?
What might happen elsewhere if I take that support away?
What information might help the body feel safe enough to organise itself differently?
This can influence treatment in several ways.
We may look beyond the painful area.
We may observe walking, weight transfer and how the person uses both sides of their body.
We may consider the relationship between the foot, pelvis, spine, jaw and nervous system.
We may choose gentler input instead of assuming that more pressure will create a better response.
And we may recognise when the wider story falls outside our professional scope and deserves referral.
A discovery doesn’t always give us another technique
Learning that bone communicates with the brain and kidneys doesn’t give us a special move for the femur.
It gives us a more interesting understanding of the person on the treatment table.
It reminds us that the body isn’t a machine assembled from separate parts.
It is a living conversation.
The painful place may be where that conversation is being heard most loudly.
It may not be where the story began.
Good therapists don’t just know more techniques. They ask better questions. And they learn to recognise the clues the body is quietly offering.
Explore more whole-body connections
If you enjoy looking beyond the obvious, download my free Therapist’s Guide to Fascia, TMJ and the Nervous System:
An email address is all you need to receive it.
Curious about Bowen?
My next Bowen Introduction Workshop is Sunday 25 October in Naarden.
It is a relaxed, practical day where therapists can experience Bowen moves and explore the relationships between fascia, the nervous system and whole-body patterns.
Visit the training page or contact me for details:
References and further reading
MC4R-dependent suppression of appetite by bone-derived lipocalin-2:
Evidence in humans for bone as an endocrine organ regulating energy metabolism:
Regulation of FGF23 production and phosphate metabolism through bone-kidney interactions:
Osteocytic FGF23 and its kidney function:
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