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What is relaxin back |
Relaxin is a polypeptide hormone belonging to
the insulin family. First discovered in 1926 by extracting an impure
form from pregnant pigs, since then relaxin has been highly purified
in both rats and pigs but a purified human extraction and
characterization of its detailed structure is still unknown. Human
relaxin-1 (RLN1), relaxin-2 (RLN2) and relaxin-3 (RLN3) are
predicted to consist of a two-chain structure and three disulfide
bonds in a disposition identical to that of insulin.
Relaxin is capable of activating RXFP1(relaxin/insulin-like
family peptide receptor 1)and RXFP2
(relaxin/insulin-like family peptide receptor 2) through the
G-protein-coupled receptor. G protein-coupled receptors (GPCRs) are a
large protein family of transmembrane receptors that sense molecules
outside the cell and activate inside signal transduction pathways and,
ultimately, cellular responses.
Relaxin is produced mainly by the corpus luteum, in both pregnant and
non-pregnant females. During menstruation the body produces relaxin that
rises to a peak within approximately 14 days of ovulation and then
declines.
In pregnant cycles, rather than subsiding, relaxin
secretions continue to rise during the first trimester and then
again in the final weeks. In males, relaxin is synthesized in the
prostate and released in the seminal fluid. During
pregnancy relaxin has a diverse range of effects, including the
production and remodelling of collagen, increase in elasticity and
relaxation of muscles, tendons and ligaments. The hormone has both
direct and indirect effects that affect the individual person as a
whole, affecting almost all parts within the body and can be broken
down into the following:
Striated and smooth muscles.
Central nervous and autonomic nervous systems.
Connective tissues in the form of skin, ligament, tendon
and cartilage.
The cardiac muscles.
A systemic deficit of the hormone relaxin and poor inability to
utilize the existing hormone produced by the body, contributes to muscle
discomfort, occasional bowel and bladder upset, digestive difficulties,
dizziness, shortness of breath, aching joints, fatigue, headaches and
emotional distress in some women.
Being on the contraceptive pill reduces the relaxin levels. It can be
suggested that use of hormonal contraceptives before the first pregnancy
may cause an increased risk of pregnancy-related pelvic pain in the
first pregnancy.(6)
High levels of relaxin are also found in pregnant women with Type 1
diabetes as well as twin pregnancies
(18)
Correlation between the concentration of the pregnancy hormone
relaxin and the stability of the hip joint in newborns indicate that
hip instability frequently occurs with decreasing relaxin
concentration.(19)
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| The Functions of Relaxin
(20)
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Promotes dilation of blood vessels in several organs and
tissues, including the uterus, the mammary gland and the heart.
Has a chronotropic action on the heart, has recently been
identified in the heart atria.
Influences the secretion of hormones by the pituitary gland.
Contributes to the regulation of fluid balance.
Use of recombinant relaxin in the treatment of systemic
sclerosis or scleroderma.
Influence renal vasodilation.
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Relaxin During pregnancy
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During pregnancy the hormone relaxin
influences such things as:
The induction of collagen remodelling and consequent softening of
the tissues of the birth canal in view of delivery by cervical
ripening and rupture of the fetal membranes at term.
The inhibition of uterine contractile activity to prevent preterm
labour.
The stimulation of growth and differentiation of the mammary
gland allowing nipple growth to occur.
Relaxin plays a role in sperm motility, fertilization,
implantation, uterine growth and accommodation; relaxin is needed to
support the establishment and maintenance of early pregnancy.
Relaxin affects collagen metabolism (chemical processes
occurring within a living cell that is necessary for the
maintenance of life), inhibiting collagen synthesis (prevent or
decrease a period in the cell cycle) and increasing matrix
metalloproteinase's (degrade extracellular matrix) that
increases collagenase production (collagenase involves enzymes
that break down the native collagen that holds animal tissues
together).
Although relaxin's main cellular action in pregnancy is to
remodel collagen by biosynthesis thus facilitating the changes of
connective tissue, it does not seem to generate musculoskeletal
problems. High levels of cortisol, estradiol, progesterone and
relaxin as well as a significant distention of the symphyseal joint
during pregnancy is not a good indicator of pelvic girdle pain.
There is no correlation between age, culture, nationality and
numbers of pregnancies that determine a higher incidence of pelvic
girdle pain.
(5)
However, if you experience pelvic girdle pain in one pregnancy you
are more likely to experience it in subsequent pregnancies; but the
severity can not be determined. Concentrations of relaxin during the
two days immediately preceding parturition are significantly greater
than all other days. After this time period relaxin is no longer
manufactured in large amounts in the postnatal period. The effects
of the hormones on the ligaments are still evident until about five
months post birth.
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Serum relaxin levels were not
associated with the degree of symphyseal distention or with pelvic
girdle pain in pregnancy.
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Estrogen
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Estrogen (also oestrone) is an estrogenic hormone secreted by
the ovary.
Estrogens are steroids.
Estrogen is one of the three estrogens, which also
include estriol and estradiol. Estrogen is the least
prevalent of the three hormones, estradiol being prevalent
almost always in a female body; estriol being prevalent
primarily during pregnancy. Functions of Estradiol
Breast development and maintenance, adding fat to
breasts, hips, thighs during puberty.
Improving bone strength and density and accelerating
bone maturation and bringing epiphyses to closure,
completing growth.
Growth of the uterus and development of the endometrial
lining to a thickness necessary to support pregnancy and
menstruation.
Thinning of cervical mucus at ovulation.
Promoting and maintaining vaginal mucosal thickness and
secretions.
Serving as the primary feedback to the brain of sex
hormone levels in both males and females.
Participating in triggering ovulation and preservation
of egg cells.
Vascular and cerebral effects.
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Estrogen During Pregnancy
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Triggers the maturation of reproductive
organs.
Help in the development of sexual characteristics.
Contributes to the increase in breast size and assists
in the lactation process.
Regulates bone density in a foetus.
Maintains the endometrium during pregnancy. This increase in
the depth and consistency of the uterine lining prepares it for
implantation.
Estrogen is also responsible for skin changes.
Maintains, regulates and triggers the production of other
hormones.
Estrogen, along with the hormone relaxin, alters pelvic
joints and ligaments, and increases mobility of nipple
tissue.
In late pregnancy, fibers of the cervix are swollen and
loosely connected to each other. This is the “ripening” that
prepares the cervix to dilate.
Protects female foetuses from the effects of androgens
in the mother's system. (Androgens are substances that have
a masculinising effect).
Estrogen is responsible for an increased blood supply
and effects the lymphatic's and nerve supply to the uterus,
and throughout the body.
Another function of estrogen is changes in the character
of tissue.
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| Glucosamine back |
| Glucosamine is an amino sugar synthesized in
the body, and is a component of proteoglycan, which is a major
structural component of cartilage. Glucosamine Sulfate is an
artificially synthesized salt of Glucosamine. Chondroitin Sulfate is
composed of repeating units of glucosamine with attached sugar
molecules. Combinations of Glucosamine and Chondroitin have been
tried in the treatment of osteoarthritis.
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Collagen
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| One of the functions of relaxin during
pregnancy is to remodel collagen. Collagen is found in all animals
and is the most abundant proteins in the human body. Collagen has
insoluble, extracellular glycoprotein's with carbohydrate attached
to them. The carbohydrate consists of short, usually branched,
chains of sugars and nitrogen-containing amino sugars. One of the
mechanisms involved in the regulation of collagen production is
G-protein linked signal transduction (a process by which a cell
converts one kind of signal which involves an ordered sequences of
biochemical reactions inside the cell.
Collagen is a fibrous protein occurring in bone, cartilage, muscle,
connective tissues and, tendons. In the skin, collagen provides texture,
resilience, and shape. In joints, it protects and stimulates anabolic
restoration of joint cartilage and synovial fluid and connective tissue.
It is a major structural protein in tissues around which cells live and
function. There is no organ or tissue which does not have collagen.
Bones and teeth are made by adding mineral crystals to collagen. It is a
natural protein that provides structural support and is found in skin It
is the most abundant protein in your body, and is necessary for the
proper functioning of joints, the production of lean muscle tissue, and
smooth, supple skin, and the growth of hair and nail. During pregnancy
Type's l, 2, 3, 5 and 6 are understood to have a significant role.
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| Chart of Collagen Types 1 to 12 of 28
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| Type 1 |
Most abundant in the human body. It is in scar tissue as
it repairs. It is found in tendons and the organic part of bone. |
| Type 2 |
Articular cartilage: the translucent cartilage found at
the ends of long bones, also called hyaline cartilage. |
| Type 3 |
Forms skin, muscle. This collagen is produced quickly by
young fibroblasts before the tougher Type I collagen is synthesized. |
| Type 4 |
Basal lamina; eye lens. Also serves as part of the
filtration system in capillaries and the glomeruli of nephron in the kidney. |
| Type 5 |
Most interstitial tissue (situated between the cells of
a structure), associated with Type I and with the placenta. |
| Type 6 |
Epithelium is a tissue that covers a surface or lines a
cavity. |
| Type 7 |
Some endothelial cells which are thin cells that line
the heart, blood vessels, lymphatics, and serous cavities. |
| Type 8 |
Found in cartilage, also associated with Type 2. |
| Type 9 |
A type of collagen which is also a proteoglycan. |
| Type 10 |
Hypertrophic (abnormal enlargement of a part or organ),
and mineralizing cartilage. |
| Type 11 | Cartilage |
| Type 12 |
FACIT collagen, interacts with type I
containing fibrils, decorin and glucosaminoglycans |
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| Cell back |
| The word cell comes from the Latin cella meaning,
"a small room". The cell is the structural and functional unit of
all living organisms. A cell wall is a more or less solid layer
surrounding a cell. The cell wall's main purpose is to actually
protect the interior from any physical movement that may damage the
cell. Osmosis is important because it provides the primary means by
which water is transported into and out of cells. The function of
osmosis is to diffuse fluid through a semi permeable membrane from a
solution with a low solute concentration to a solution with a higher
solute concentration until there is an equal concentration of fluid
on both sides of the membrane, this flow will slow and finally stop
as the pressure becomes such that the diffusion in each direction is
equal.
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Bone back |
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Bone has an internal mesh-like structure, the density of which may vary
at different points. Bone can be either compact or cancellous (spongy)
During the first and second trimester of pregnancy bone remodelling is
uncoupled. Serum calcium decreases as bone resorption peaks in late
pregnancy. There are significant decreases in bone mineral density at sites
rich in trabecular bone, such as the lumbar spine and the trochanter.
(21)
Bone cells include: osteoblasts, osteocytes and osteoclasts.
Osteoclasts
Osteoclasts are large cells that dissolve the bone. They are found on
the surface of the bone mineral next to the dissolving bone.
Osteocytes
Osteocytes are cells inside the bone. They also come from osteoblasts.
Some of the osteoblasts turn into osteocytes while the new bone is being
formed, and the osteocytes then get surrounded by new bone. These cells can
sense pressures or cracks in the bone and help to direct where osteoclasts
will dissolve the bone.
Osteoblasts
Osteoblasts are the cells that form new bone. They also come from
the bone marrow and are related to structural cells. Osteoblasts work in
teams to build bone. They produce new bone called "osteoid" which is
made of bone collagen and other protein. Then they control calcium and
mineral deposition. They are found on the surface of the new bone.
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