The capsule is important for the physiological function of the kidney as it influences interstitial pressure and therefore tubular reabsorption of sodium and water. Decapsulation blunts the pressure natriuretic response, for example.

In addition to the previous answer, the peritoneum will adhere to the kidney encapsulating it and forming scars

In a practical way, you must think that every structure has a function. When we make a kidney transplantation, and a significant portion of the renal capsule is lost, we often cover the defect with other material ( a mesh) to prevent parenchymal bleeding .....that is the most usual consequence

How about considering the influence of tissue non-specific signal proteins once the renal caspsule has been removed?

Please elaborate

The interlobar arteries are responsible for providing the blood supply to the renal capsule. These are small blood vessels that branch out from the primary renal arteries. The interlobar arteries travel through the outer portion of the kidneys known as the renal cortex and terminate once they reach the renal capsule.

If this important covering is damaged, whether by a traumatic event or as part of a naturally occurring disease, there is a risk of developing decreased kidney function. If the amount of function decreases significantly, the patient may begin to experience kidney failure, also referred to as renal failure.

Well, cells express signal-proteins which influence cell behavior of their direct vicinity (paracrine secretion) and in remote areas as well. Tissue homöostasis is a balance of apoptosis and cell division within the cell mass of an organ. Signal-proteins thus are a critical component of tissue turnover and organ specific cell mass maintenance. The capsule consisting of fibrous tissue in this view represents some kind of a barrier which ultimately prevents the influence of signal proteins from other cell masses. It can perhaps be considered the result of a competitive situation of signal proteins of different cell origin at the surface of an organ.

There must exist this kind of "protecting barrier" because otherwise tissue homöostasis, tissue turnover and healing wouldn't be possible.

There are many examples. Almost all organs have a capsule like this.

What do you think?

It is pure logic. So the renal capsule is not just a physical barrier, it is also a functional one.

I have a question, does the endocrine part of pancreas have a similar barrier separating its from the exocrine part, they are so different functionally......

I'm not familiar with the microanatomy of pancreas, but I would assume that the answer is yes, if you look at the histology of the islet cell apparatus which is clearly separated from the exocrine cell mass by a circular layer of connective tissue;

Another example are muscle packs of the thigh which are separated into different parts by fibrous tissue.

To my knowledge it has not vet been cleared if in this way separated muscle cell masses have also a distinguishable DNA methylation state like the cornea has compared to a neuron, although being muscle cells as such.