Does the skeleton play a role in the endocrine system?
These advances point to the skeleton as an endocrine organ that modulates glucose tolerance and testosterone production by secretion of a bone-specific protein, osteocalcin. This review will detail how bone has emerged as a bona-fide endocrine “gland”, and with that, the potential therapeutic implications that could be realized for this hormone-secreting tissue.
What is bone for?
Bone as an endocrine organ Bone has classically been viewed as an inert structure that is necessary for mobility, calcium homeostasis, and maintenance of the hematopoietic niche. Recent advances in bone biology using complex genetic manipulations in mice have highlighted the importance of bone not only as a structural scaffol …
Is the human skeleton a scaffold or endocrine organ?
Feb 08, 2022 · A major and recent advance of skeletal biology has been the realization that bone is an endocrine organ. One hormone secreted by the osteoblasts, the bone-forming cells, osteocalcin affects glucose homeostasis, energy expenditure and male fertility.
What is the function of OCN in bone?
Jan 01, 2014 · A major and recent advance of skeletal biology has been the realization that bone is an endocrine organ. One hormone secreted by the osteoblasts, the bone-forming cells, osteocalcin affects glucose homeostasis, energy expenditure and male fertility.
Is a bone an organ?
Bones are often thought of as static structures which only offer structural support. However, they truly function as an organ. Like other organs, bones are valuable and have many functions.Jul 26, 2021
What is endocrine bone?
The thyroid, parathyroid, pituitary, or adrenal glands, and the pancreas are parts of the endocrine system, and, therefore are associated with the endocrine bone disease. Some common endocrine disorders are hypothyroidism, hyperthyroidism, Paget's disease, Osteoporosis, and diabetes.
What is an endocrine organ?
An organ that makes hormones that are released directly into the blood and travel to tissues and organs all over the body. Endocrine glands help control many body functions, including growth and development, metabolism, and fertility. Some examples of endocrine glands are the pituitary, thyroid, and adrenal glands.
Is Bone Marrow an endocrine organ?
Bone Marrow Adipose Tissue Is an Endocrine Organ that Contributes to Increased Circulating Adiponectin during Caloric Restriction.Aug 5, 2014
Which hormone is secreted by bone?
Our bones secrete a protein called osteocalcin, discovered in the 1970s, that rebuilds the skeleton. In 2007, Karsenty and colleagues discovered that this protein acts as a hormone to keep blood sugar levels in check and burn fat.
Do bone tissues produce hormones?
Bone is essential for mobility, calcium homeostasis, and hematopoietic function. Recently, advances in bone biology have highlighted the importance of skeleton as an endocrine organ (1). In fact, hormones produced by bone cells can control mineral ion homeostasis (i.e., FGF23) and energy balance (i.e., osteocalcin).Dec 19, 2017
Is breast an endocrine organ?
These cases illustrate that the mammary gland is not just a gland which delivers milk in response to certain stimuli, but that it also transmits humoral signals, i.e., the mammary gland is an endocrine gland.
What are the 5 endocrine glands?
While many parts of the body make hormones, the major glands that make up the endocrine system are the:hypothalamus.pituitary.thyroid.parathyroids.adrenals.pineal body.the ovaries.the testes.
Is the liver a endocrine gland?
The liver is essentially an exocrine gland, secreting bile into the intestine. But, the liver is also -- and significantly so -- an endocrine gland and a blood filter.Mar 9, 2022
Is blood an organ?
This chapter reveals that blood, which constitutes approximately 8% of human body weight, is one of the largest organs and the main means of transport for the exchange of substances between the organs. Blood plays an important role in the defense and repair processes of the body.
What cells are found in the periosteum?
Periosteum and endosteum contain cells (osteoblasts, osteoclasts, and osteoprogenitor cells) required for bone development and remodeling of the bone.
What are bone marrows?
(bone MAYR-oh) The soft, spongy tissue that has many blood vessels and is found in the center of most bones. There are two types of bone marrow: red and yellow. Red bone marrow contains blood stem cells that can become red blood cells, white blood cells, or platelets.
Why is bone important?
Bone has classically been viewed as an inert structure that is necessary for mobility, calcium homeostasis, and maintenance of the hematopoietic niche. Recent advances in bone biology using complex genetic manipulations in mice have highlighted the importance of bone not only as a structural scaffol ….
Is bone an endocrine organ?
Bone as an endocrine organ. Bone has classically been viewed as an inert structure that is necessary for mobility, calcium homeostasis, and maintenance of the hematopoietic niche.
What is the function of bone?
The first one is that it is the only tissue in the body that contains a cell type, the osteoclast, whose function is to destroy (resorb) the host tissue.
What is the main endocrine pathway that regulates male fertility?
The main endocrine pathway regulating male fertility is the hypothalamo–pituitary axis, in which luteinizing hormone (LH), a heterodimer between an α-subunit common to several peptide hormones and a β-subunit specific to LH, favors testosterone biosynthesis. Although less severe, the reproductive phenotype of Osteocalcin −/− and Gprc6a−/− male mice bears resemblance to the one seen in Lhb−/− (LH-deficient) male mice, as they are both characterized by a defect in testosterone synthesis and testosterone-dependent events. 43., 44. Yet, a remarkable feature of the reproduction phenotype observed in Osteocalcin−/− or Gprc6a−/− mice is that it develops in the face of an increase in circulating levels of LH. This situation raised the following question: Does osteocalcin act downstream of LH or does the realization that osteocalcin regulates male fertility reveal the existence of two different pathways, both necessary for male fertility, one pituitary-dependent and one bone-dependent? To address this question, rescue analysis was undertaken of the Lhb−/− or Osteocalcin−/− mice with either osteocalcin or human chorionic gonadotropin (hCG), respectively.
Is osteoporosis a disease after menopause?
Besides these biological and clinical observations, one of the most established features of bone pathology is that osteoporosis, a low bone mass disease, appears after menopause. 11., 12., 13. In other words, there is a regulation of bone mass by sex steroid hormones. Thus, one could ask: is there an endocrine regulation ...
Does insulin affect osteoblasts?
Thus insulin signaling in osteoblasts favors acidification of the bone ECM, a necessary component of bone resorption. In a superb example of functional dependence between organs, this bone (re)modeling-related function of insulin signaling in osteoblasts has, in fact, major implications for glucose homeostasis.
Is osteocalcin a hormone?
A second legitimate question that has plagued osteocalcin research since this molecule was recognized to be a hormone in rodents has been to determine whether it also has an endocrine function in humans. The function of osteocalcin as a regulator of testosterone production has been recently extended to humans. It was recently shown in humans that osteocalcin and bone turnover is associated with testosterone circulating levels in the general population and in patients with bone disorders.45 Moreover, Dr. Khosla’s group also showed that there is a significant association between serum osteocalcin and testosterone levels during mid-puberty in males. 46 They postulate that this axis may be most relevant during rapid skeletal growth in adolescent human males to help maximize bone size. However, while there is a growing body of evidence that osteocalcin serum levels are a reliable indicator of the degree of insulin secretion, insulin sensitivity, and circulating serum testosterone levels in humans, 24., 47. there was, until recently, no genetic evidence establishing that osteocalcin fulfills its endocrine functions in humans.
Is osteocalcin an endocrine organ?
A major and recent advance of skeletal biology has been the realization that bone is an endocrine organ. One hormone secreted by the osteoblasts, the bone-forming cells, osteocalcin affects glucose homeostasis, energy expenditure and male fertility. This chapter will review the particularities of the mechanism of activation of osteocalcin, its mode of action and what it reveals for our understanding of the regulation of glucose homeostasis and male fertility. We will also present how the identification of a specific receptor for osteocalcin has allowed to verify that it has the same function in humans as in the mouse.
What hormones are produced by bone?
Although bone has long been recognized as a target for hormones influencing calcium and phosphorus homeostasis and bone structure, recent evidence shows that the skeleton itself produces at least two hormones, fibroblast growth factor 23 (FGF23) and osteocalcin. FGF23 is produced by osteocytes in bone and acts on the kidney to inhibit 1α-hydroxylation of vitamin D and promote phosphorus excretion. Mouse genetics studies revealed that the osteoblast product, osteocalcin, acts on the pancreatic β-cell to enhance insulin production and on peripheral tissues to increase glucose utilization as a result of increased insulin sensitivity and to reduce visceral fat. This review highlights the recent studies indicating bone's role as an endocrine organ.
How does the skeleton help us?
The concept of the skeleton as a ductless gland, responding to environmental influences of metabolism and energy requirements by producing a hormone with such actions, is a revolutionary one. It helps us realize the importance of the skeleton in mammalian survival, confirmed by the remarkable number of dramatic bone phenotypes emerging as the result of genetic manipulation of mice. It makes evolutionary sense that bone produces a hormone that regulates the metabolism of phosphate, cooperating with other hormones to do so and thereby influencing skeletal mineralization. Likewise, the importance of the skeleton in survival of animals is obvious, and energy is required for survival, hence the development of a control system through an endocrine pathway to link bone to energy metabolism.
What is the role of FGF23 in the kidney?
The discovery of FGF23 revealed a tightly controlled system regulating serum phosphate and 1,25-dihydroxyvitamin D [1,25 (OH)2 D] levels, produced in bone and acting on the kidney through a specific receptor ( Figure 1 ). This newly discovered regulation of serum phosphate by FGF23 is independent of PTH or the vitamin D endocrine system 3, 4, which are already known to affect serum phosphate levels. Furthermore, FGF23 excess or deficiency resulted in several abnormalities of phosphate metabolism. Bone is formed as a hard tissue by deposition of hydroxyapatite [Ca10 (PO) 4 (OH) 2] crystals upon bone matrix produced by osteoblasts. Although detailed mechanisms of mineralization of bone matrix remain to be clarified, chronic hypophosphatemia impairs this process and hyperphosphatemia causes ectopic calcification, as exemplified by several diseases, explained below. These findings identify the skeleton as an endocrine organ, enable several abnormalities of phosphate and vitamin D metabolism to be classified as endocrine diseases and provide a new hormone to explain a paraneoplastic syndrome called tumor-induced osteomalacia (TIO).
What hormone increases insulin production and sensitivity?
Even greater surprises came from the discovery of the osteoblast-specific protein osteocalcin . Loss- and gain-of-function studies and pharmacological experiments in mice have shown osteocalcin to be a hormone that increases insulin production and sensitivity, enhancing glucose utilization and energy expenditure [54]. These findings have been reviewed recently in TEM [55].
Where is FGF23 expressed?
Although FGF23 seemed to be predominantly expressed in the ventrolateral thalamic nucleus in mice [5], weak FGF23 expression was also observed in liver, heart, thymus and lymph node [7]. Attractive though the idea was that FGF23 is a hormone, it was essential to identify the site of the ‘gland’. Several studies pointed to bone as a primary site of FGF23 production. First, knock-in of the LacZ gene into the FGF23 locus indicated that FGF23 is predominantly expressed in bone after birth [12]. Second, expression of FGF23 protein was observed in human bone by immunohistochemistry [14]. Third, in murine models of enhanced FGF23 production, FGF23 expression was observed clearly in osteocytes 15, 16. Fourth, in vitro studies supported the notion that FGF23 is expressed in bone 17, 18. Moreover, FGF23 expression has not been reported in kidney [7], the site of its action, and an enzyme-linked immunosorbent assay for FGF23 indicated that FGF23 is present in normal circulation 19, 20. These results indicate that FGF23 is probably produced by osteocytes in bone, circulates as a hormone and acts on the kidney to influence vitamin D and phosphate metabolism and, hence, bone mineralization.
What does boning a girl mean?
Noun. boning (plural bonings) The removal of bones from fish etc; filleting. The arrangement of bones in a corset. (slang, vulgar) An act of sexual intercourse.
Are teeth bones?
Teeth consist mostly of hard, inorganic minerals like calcium. They also contain nerves, blood vessels and specialized cells. But they are not bones. Teeth don't have the regenerative powers that bones do and can't grow back together if broken.
Are teeth an organ?
The tooth is an amazing sensory organ. The outside of the tooth, the enamel, is the hardest tissue in the human body. The pulp contains blood vessels, nerve fibers and other connective tissue. Although the pulp has several functions, including the formation of dentin, the sensory function of teeth is quite interesting.
Are veins an organ?
Veins are elastic tubes, or blood vessels, that carry blood from your organs and tissues of the body back to your heart. Each vein is made up of three layers: A layer of membranous tissue on the inside.
Are bones alive?
Bones in our body are living tissue. They have their own blood vessels and are made of living cells, which help them to grow and to repair themselves. As well, proteins, minerals and vitamins make up the bone.
What is bone made of?
Made mostly of collagen, bone is living, growing tissue. Collagen is a protein that provides a soft framework, and calcium phosphate is a mineral that adds strength and hardens the framework. This combination of collagen and calcium makes bone strong and flexible enough to withstand stress.
How strong is a bone?
Bone is extraordinarily strong — ounce for ounce, bone is stronger than steel, since a bar of steel of comparable size would weigh four or five times as much. A cubic inch of bone can in principle bear a load of 19,000 lbs.
Much more to bone than you might have thought
Until recently, endocrinologists have looked upon bone as a target for hormones such as sex steroids, parathyroid hormone (PTH) and calcitonin.
The bone-derived hormone FGF23
The discovery of FGF23 revealed a tightly controlled system regulating serum phosphate and 1,25-dihydroxyvitamin D [1,25 (OH) 2 D] levels, produced in bone and acting on the kidney through a specific receptor ( Figure 1 ). This newly discovered regulation of serum phosphate by FGF23 is independent of PTH or the vitamin D endocrine system [
FGF23 action
Cloning and characterization of FGF23 as a causative factor of tumor-induced osteomalacia.
Sites of FGF23 production and receptor interactions
Identification of a novel fibroblast growth factor, FGF-23, preferentially expressed in the ventrolateral thalamic nucleus of the brain.
Diseases caused by aberrant FGF23 actions
Many diseases have been found to be caused by aberrant actions of FGF23 ( Table 1 ). An in vitro study indicated that FGF23 protein can be cleaved into inactive fragments between Arg179 and Ser180 by subtilisin-like proteases [
Osteocalcin, a bone hormone controlling energy metabolism
Even greater surprises came from the discovery of the osteoblast-specific protein osteocalcin. Loss- and gain-of-function studies and pharmacological experiments in mice have shown osteocalcin to be a hormone that increases insulin production and sensitivity, enhancing glucose utilization and energy expenditure [
Clinical diabetes and osteocalcin
The implications of these discoveries for type II diabetes and the metabolic syndrome are many, as are those for physiology in general. There are few recent clinical studies, and further information will evoke much interest.
