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The levels of relaxin are not a reliable indicator for the degree
of pelvic girdle pain.
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| What is relaxin back
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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.(154)
High levels of relaxin are also found in pregnant women with Type 1
diabetes as well as twin pregnancies(156)
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.(159)
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| The Functions of Relaxin
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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 back |
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.(92) 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.
Estrogen During Pregnancy
backTriggers 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.
Below is a 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. |
| 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 remodeling 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.
(78)
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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