All Topics  
Human placental lactogen

 

 
   Email Print
   Bookmark   Link
 

 

Human placental lactogen
 
 
  Topics Human placental lactogen Topic Home

Human placental lactogen (HPL), also called human chorionic somatomammotropin, is a polypeptide placenta
Placenta

The placenta or afterbirth is a highly vascularized ephemeral organ present in Placentalia vertebrates that connects the developing fetal tissues to the uterine wall....
l hormone. Its structure and function is similar to that of human growth hormone
Growth hormone

Growth hormone is a peptide hormone. It stimulates human development and cell reproduction in humans and other animals. It is a 191-amino acid, single chain polypeptide hormone which is synthesized, stored, and secreted by the somatotroph cells within the lateral wings of the anterior pituitary gland....
. It modifies the metabolic state of the mother during pregnancy
Pregnancy

Pregnancy is the carrying of one or more offspring, known as a fetus or embryo, inside the uterus of a female. In a pregnancy, there can be multiple gestations, as in the case of twins or Multiple birth....
 to facilitate the energy supply of the fetus
Fetus

A fetus is a developing mammal or other viviparous vertebrate, after the embryonic stage and before childbirth. The plural is fetuses, or sometimes feti....
. HPL is an anti-insulin
Insulin

Insulin is a hormone with extensive effects on both metabolism and several other body systems . Insulin causes most of the body's cells to take up glucose from the blood , storing it as glycogen in the liver and muscle, and stops use of fat as an energy source....
.

consists of 190 amino acids that are linked by two disulfite bonds and is secreted by the syncytiotrophoblast
Syncytiotrophoblast

Syncytiotrophoblasts are multinucleated cells found in the placenta of embryos.They are the outer syncytial layer of the trophoblasts and actively invade the uterus....
 during pregnancy.






Discussion
Ask a question about 'Human placental lactogen'
Start a new discussion about 'Human placental lactogen'
Answer questions from other users
Full Discussion Forum



Encyclopedia


Human placental lactogen (HPL), also called human chorionic somatomammotropin, is a polypeptide placenta
Placenta

The placenta or afterbirth is a highly vascularized ephemeral organ present in Placentalia vertebrates that connects the developing fetal tissues to the uterine wall....
l hormone. Its structure and function is similar to that of human growth hormone
Growth hormone

Growth hormone is a peptide hormone. It stimulates human development and cell reproduction in humans and other animals. It is a 191-amino acid, single chain polypeptide hormone which is synthesized, stored, and secreted by the somatotroph cells within the lateral wings of the anterior pituitary gland....
. It modifies the metabolic state of the mother during pregnancy
Pregnancy

Pregnancy is the carrying of one or more offspring, known as a fetus or embryo, inside the uterus of a female. In a pregnancy, there can be multiple gestations, as in the case of twins or Multiple birth....
 to facilitate the energy supply of the fetus
Fetus

A fetus is a developing mammal or other viviparous vertebrate, after the embryonic stage and before childbirth. The plural is fetuses, or sometimes feti....
. HPL is an anti-insulin
Insulin

Insulin is a hormone with extensive effects on both metabolism and several other body systems . Insulin causes most of the body's cells to take up glucose from the blood , storing it as glycogen in the liver and muscle, and stops use of fat as an energy source....
.

Structure

HPL consists of 190 amino acids that are linked by two disulfite bonds and is secreted by the syncytiotrophoblast
Syncytiotrophoblast

Syncytiotrophoblasts are multinucleated cells found in the placenta of embryos.They are the outer syncytial layer of the trophoblasts and actively invade the uterus....
 during pregnancy. Its molecular weight is 22,125. Like human growth hormone HPL is encoded by genes on chromosome
Chromosome

A chromosome is an organized structure of DNA and protein that is found in Cell . A chromosome is a single piece of DNA that contains many genes, regulatory sequence and other genetic sequence....
 17q22-24. Its biologic half-life is 15 minutes.

Levels

HPL is only present during pregnancy with maternal serum levels rising in relation to the growth of the fetus and placenta. Maximum levels are reached near term, typically to 5–7 mg/ml. Higher levels are noted in patients with multiple gestation. Little HPL enters the fetal circulation.

Function

In a bioassay
Bioassay

Bioassay is a shorthand commonly used term for biological assay and is a type of scientific experiment. Bioassays are essential in the development of new drugs, and monitoring pollutants in the environment....
 HPL mimics the action of prolactin
Prolactin

Prolactin or Luteotropic hormone is a peptide hormone primarily associated with lactation. In breastfeeding, the act of an infant suckling the nipple stimulates the production of prolactin, which fills the breast with milk via a process called lactogenesis, in preparation for the next feed....
, yet it is unclear if HPL has any role in human lactation
Lactation

Lactation describes the secretion of milk from the mammary glands, the process of providing that milk to the young, and the period of time that a mother lactates to feed her young....
.

HPL affects the metabolic system of the maternal organism. HPL decreases maternal insulin
Insulin

Insulin is a hormone with extensive effects on both metabolism and several other body systems . Insulin causes most of the body's cells to take up glucose from the blood , storing it as glycogen in the liver and muscle, and stops use of fat as an energy source....
 sensitivity, and therefore raises maternal blood glucose levels, whilst decreasing maternal glucose utilization, which helps ensure adequate fetal nutrition (the mother responds by pancreatic endocrine upregulation; this is thought to represent an evolutionary 'arms-race' resulting from the conflict of interest between mother and fetus). Chronic hypoglycemia
Hypoglycemia

Hypoglycaemia or hypoglycemia is the medical term for a Pathology state produced by a lower than normal level of Blood glucose. The term hypoglycemia literally means "under-sweet blood" ....
 leads to a rise in HPL. HPL induces lipolysis
Lipolysis

Lipolysis is the breakdown of fat stored in fat cells. During this process, free fatty acids are released into the bloodstream and circulate throughout the body....
 with the release of free fatty acids. With fasting and release of HPL, free fatty acids become available for the maternal organism as fuel, so that relatively more glucose
Glucose

Glucose , a monosaccharide also known as grape sugar, blood sugar, or corn sugar, is a very important carbohydrate in biology....
 can be utilized by the fetus. Also, ketone
Ketone

In organic chemistry, a ketone is a type of organic compound which contains a carbonyl group bonded to two other carbon atoms in the form:Neither of the substituents R1 and R2 may be equal to hydrogen ....
s formed from free fatty acids can cross the placenta
Placenta

The placenta or afterbirth is a highly vascularized ephemeral organ present in Placentalia vertebrates that connects the developing fetal tissues to the uterine wall....
 and be used by the fetus. These functions help support fetal nutrition even in the case of maternal malnutrition.

HPL has weak actions similar to growth hormone in that it causes the formation of protein tissues, and has a similar chemical structure to growth hormone, but 100 times more HPL than growth hormone is required to promote growth.

Clinical measurement of HPL

While HPL has been used as an indicator of fetal well-being and growth, other fetal monitoring methods have been found to be more reliable. Also, normal pregnancies have been reported with undetectable maternal levels of HPL.

External links