Prostaglandin
Encyclopedia
Lipid
Lipids constitute a broad group of naturally occurring molecules that include fats, waxes, sterols, fat-soluble vitamins , monoglycerides, diglycerides, triglycerides, phospholipids, and others...
compounds that are derived enzymatically from fatty acid
Fatty acid
In chemistry, especially biochemistry, a fatty acid is a carboxylic acid with a long unbranched aliphatic tail , which is either saturated or unsaturated. Most naturally occurring fatty acids have a chain of an even number of carbon atoms, from 4 to 28. Fatty acids are usually derived from...
s and have important functions in the animal
Animal
Animals are a major group of multicellular, eukaryotic organisms of the kingdom Animalia or Metazoa. Their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later on in their life. Most animals are motile, meaning they can move spontaneously and...
body. Every prostaglandin contains 20 carbon
Carbon
Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...
atoms, including a 5-carbon ring.
They are mediators and have a variety of strong physiological
Physiology
Physiology is the science of the function of living systems. This includes how organisms, organ systems, organs, cells, and bio-molecules carry out the chemical or physical functions that exist in a living system. The highest honor awarded in physiology is the Nobel Prize in Physiology or...
effects, such as regulating the contraction and relaxation of smooth muscle tissue. Prostaglandins are not endocrine hormone
Hormone
A hormone is a chemical released by a cell or a gland in one part of the body that sends out messages that affect cells in other parts of the organism. Only a small amount of hormone is required to alter cell metabolism. In essence, it is a chemical messenger that transports a signal from one...
s, but autocrine or paracrine, which are locally acting messenger molecules. They differ from hormones in that they are not produced at a discrete site but in many places throughout the human body. Also, their target cells are present in the immediate vicinity of the site of their secretion
Secretion
Secretion is the process of elaborating, releasing, and oozing chemicals, or a secreted chemical substance from a cell or gland. In contrast to excretion, the substance may have a certain function, rather than being a waste product...
(of which there are many).
The prostaglandins, together with the thromboxane
Thromboxane
Thromboxane is a member of the family of lipids known as eicosanoids. The two major thromboxanes are thromboxane A2 and thromboxane B2. The distinguishing feature of thromboxanes is a 6-membered ether-containing ring....
s and prostacyclin
Prostacyclin
Prostacyclin is a member of the family of lipid molecules known as eicosanoids.As a drug, it is also known as "epoprostenol". The terms are sometimes used interchangeably.-History:...
s, form the prostanoid
Prostanoid
Prostanoid is the term used to describe a subclass of eicosanoids consisting of: the prostaglandins , the thromboxanes and the prostacyclins - Biosynthesis : Cyclooxygenase catalyzes the conversion of the free essential fatty acids to...
class of fatty acid derivatives, a subclass of eicosanoid
Eicosanoid
In biochemistry, eicosanoids are signaling molecules made by oxidation of twenty-carbon essential fatty acids, ....
s.
History and name
The name prostaglandin derives from the prostate gland. When prostaglandin was first isolated from seminal fluid in 1935 by the Swedish physiologistPhysiology
Physiology is the science of the function of living systems. This includes how organisms, organ systems, organs, cells, and bio-molecules carry out the chemical or physical functions that exist in a living system. The highest honor awarded in physiology is the Nobel Prize in Physiology or...
Ulf von Euler
Ulf von Euler
Ulf Svante von Euler was a Swedish physiologist and pharmacologist. He won a Nobel Prize in Physiology or Medicine in 1970 for his work on neurotransmitters.-Life:...
, and independently by M.W. Goldblatt, it was believed to be part of the prostatic secretions. (In fact, prostaglandins are produced by the seminal vesicles). It was later shown that many other tissues secrete prostaglandins for various functions. The first total syntheses
Total synthesis
In organic chemistry, a total synthesis is, in principle, the complete chemical synthesis of complex organic molecules from simpler pieces, usually without the aid of biological processes. In practice, these simpler pieces are commercially available in bulk and semi-bulk quantities, and are often...
of prostaglandin F2α and prostaglandin E2 were reported by E. J. Corey in 1969, an achievement for which he was awarded the Japan Prize
Japan Prize
is awarded to people from all parts of the world whose "original and outstanding achievements in science and technology are recognized as having advanced the frontiers of knowledge and served the cause of peace and prosperity for mankind."- Explanation :...
in 1989.
In 1971, it was determined that aspirin
Aspirin
Aspirin , also known as acetylsalicylic acid , is a salicylate drug, often used as an analgesic to relieve minor aches and pains, as an antipyretic to reduce fever, and as an anti-inflammatory medication. It was discovered by Arthur Eichengrun, a chemist with the German company Bayer...
-like drugs could inhibit the synthesis of prostaglandins. The biochemist
Biochemist
Biochemists are scientists who are trained in biochemistry. Typical biochemists study chemical processes and chemical transformations in living organisms. The prefix of "bio" in "biochemist" can be understood as a fusion of "biological chemist."-Role:...
s Sune K. Bergström, Bengt I. Samuelsson
Bengt I. Samuelsson
-External links:**...
and John R. Vane jointly received the 1982 Nobel Prize in Physiology or Medicine
Nobel Prize in Physiology or Medicine
The Nobel Prize in Physiology or Medicine administered by the Nobel Foundation, is awarded once a year for outstanding discoveries in the field of life science and medicine. It is one of five Nobel Prizes established in 1895 by Swedish chemist Alfred Nobel, the inventor of dynamite, in his will...
for their research on prostaglandins.
Biosynthesis
Platelet
Platelets, or thrombocytes , are small,irregularly shaped clear cell fragments , 2–3 µm in diameter, which are derived from fragmentation of precursor megakaryocytes. The average lifespan of a platelet is normally just 5 to 9 days...
s, endothelium
Endothelium
The endothelium is the thin layer of cells that lines the interior surface of blood vessels, forming an interface between circulating blood in the lumen and the rest of the vessel wall. These cells are called endothelial cells. Endothelial cells line the entire circulatory system, from the heart...
, uterine
Uterus
The uterus or womb is a major female hormone-responsive reproductive sex organ of most mammals including humans. One end, the cervix, opens into the vagina, while the other is connected to one or both fallopian tubes, depending on the species...
and mast cell
Mast cell
A mast cell is a resident cell of several types of tissues and contains many granules rich in histamine and heparin...
s. They are synthesized in the cell from the essential fatty acid
Essential fatty acid
Essential fatty acids, or EFAs, are fatty acids that humans and other animals must ingest because the body requires them for good health but cannot synthesize them...
s (EFAs).
An intermediate is created from phospholipase-A2
Phospholipase A2
Phospholipases A2 are enzymes that release fatty acids from the second carbon group of glycerol. This particular phospholipase specifically recognizes the sn-2 acyl bond of phospholipids and catalytically hydrolyzes the bond releasing arachidonic acid and lysophospholipids...
, then brought out of one of either the cyclooxygenase pathway
Cyclooxygenase
Cyclooxygenase is an enzyme that is responsible for formation of important biological mediators called prostanoids, including prostaglandins, prostacyclin and thromboxane. Pharmacological inhibition of COX can provide relief from the symptoms of inflammation and pain...
or the lipoxygenase pathway
Lipoxygenase
Lipoxygenases are a family of iron-containing enzymes that catalyse the dioxygenation of polyunsaturated fatty acids in lipids containing a cis,cis-1,4- pentadiene structure. It catalyses the following reaction:...
to form either prostaglandin and thromboxane or leukotriene
Leukotriene
Leukotrienes are fatty signaling molecules. They were first found in leukocytes . One of their roles is to trigger contractions in the smooth muscles lining the trachea; their overproduction is a major cause of inflammation in asthma and allergic rhinitis...
respectively. The cyclooxygenase pathway produces thromboxane
Thromboxane
Thromboxane is a member of the family of lipids known as eicosanoids. The two major thromboxanes are thromboxane A2 and thromboxane B2. The distinguishing feature of thromboxanes is a 6-membered ether-containing ring....
, prostacyclin
Prostacyclin
Prostacyclin is a member of the family of lipid molecules known as eicosanoids.As a drug, it is also known as "epoprostenol". The terms are sometimes used interchangeably.-History:...
and prostaglandin D, E and F. The lipoxygenase enzyme pathway is inactive in leukocytes and in macrophage
Macrophage
Macrophages are cells produced by the differentiation of monocytes in tissues. Human macrophages are about in diameter. Monocytes and macrophages are phagocytes. Macrophages function in both non-specific defense as well as help initiate specific defense mechanisms of vertebrate animals...
s and synthesizes leukotrienes.
| Name | EFA Type | Series >- | Gamma-linolenic acid Gamma-Linolenic acid γ-Linolenic acid is a fatty acid found primarily in vegetable oils... (GLA) via DGLA Dihomo-gamma-linolenic acid Dihomo-γ-linolenic acid is a 20-carbon ω−6 fatty acid. In physiological literature, it is given the name 20:3 . DGLA is a carboxylic acid with a 20-carbon chain and three cis double bonds; the first double bond is located at the sixth carbon from the omega end. DGLA is the elongation product... |
ω-6 Omega-6 fatty acid n−6 fatty acids are a family of unsaturated fatty acids that have in common a final carbon–carbon double bond in the n−6 position, that is, the sixth bond, counting from the methyl end.The biological effects of the n−6 fatty acids are largely mediated by their conversion to n-6 eicosanoids... |
>- | ω-6 | >- | ω-3 Omega-3 fatty acid N−3 fatty acids are essential unsaturated fatty acids with a double bond starting after the third carbon atom from the end of the carbon chain.... |
series-3 |
Release of prostaglandins from the cell
Prostaglandins were originally believed to leave the cells via passive diffusion because of their high lipophilicity. The discovery of the prostaglandin transporterProstaglandin transporter
Prostaglandin transporter is a protein which carries prostaglandin across cell membranes....
(PGT, SLCO2A1), which mediates the cellular uptake of prostaglandin, demonstrated that diffusion alone cannot explain the penetration of prostaglandin through the cellular membrane. The release of prostaglandin has now also been shown to be mediated by a specific transporter, namely the multidrug resistance protein 4 (MRP4, ABCC4), a member of the ATP-binding cassette transporter superfamily. Whether MRP4 is the only transporter releasing prostaglandins from the cells is still unclear.
Cyclooxygenases
Prostaglandins are produced following the sequential oxidation of AA, DGLA or EPA by cyclooxygenaseCyclooxygenase
Cyclooxygenase is an enzyme that is responsible for formation of important biological mediators called prostanoids, including prostaglandins, prostacyclin and thromboxane. Pharmacological inhibition of COX can provide relief from the symptoms of inflammation and pain...
s (COX-1 and COX-2) and terminal prostaglandin synthases. The classic dogma is as follows:
- COX-1 is responsible for the baseline levels of prostaglandins.
- COX-2 produces prostaglandins through stimulation.
However, while COX-1 and COX-2 are both located in the blood vessels, stomach
Stomach
The stomach is a muscular, hollow, dilated part of the alimentary canal which functions as an important organ of the digestive tract in some animals, including vertebrates, echinoderms, insects , and molluscs. It is involved in the second phase of digestion, following mastication .The stomach is...
and the kidneys, prostaglandin levels are increased by COX-2 in scenarios of inflammation
Inflammation
Inflammation is part of the complex biological response of vascular tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. Inflammation is a protective attempt by the organism to remove the injurious stimuli and to initiate the healing process...
.
Prostaglandin E synthase
Prostaglandin E2 (PGE2) is generated from the action of prostaglandin E synthaseProstaglandin E synthase
Prostaglandin E synthase is an enzyme involved in eicosanoid and glutathione metabolism, a member of MAPEG family. It generates prostaglandin E from prostaglandin H2.The synthase generating PGE2 is a membrane-associated protein....
s on prostaglandin H2 (PGH2). Several prostaglandin E synthases have been identified. To date, microsomal prostaglandin E synthase-1 emerges as a key enzyme in the formation of PGE2.
Other terminal prostaglandin synthases
Terminal prostaglandin synthases have been identified that are responsible for the formation of other prostaglandins. For example, hematopoietic and lipocalinLipocalin
The lipocalins are a family of proteins which transport small hydrophobic molecules such as steroids, bilins, retinoids, and lipids. They share limited regions of sequence homology and a common tertiary structure architecture...
prostaglandin D synthases (hPGDS and lPGDS) are responsible for the formation of PGD2 from PGH2. Similarly, prostacyclin (PGI2) synthase (PGIS) converts PGH2 into PGI2. A thromboxane synthase (TxAS
Thromboxane-A synthase
Thromboxane A synthase 1 , also known as TBXAS1, is an enzyme that, in humans, is encoded by the TBXAS1 gene.- Function :This gene encodes a member of the cytochrome P450 superfamily of enzymes...
) has also been identified.
Prostaglandin-F synthase
Prostaglandin-F synthase
In enzymology, a prostaglandin-F synthase is an enzyme that catalyzes the chemical reaction--9alpha,11alpha,15-trihydroxyprosta-5,13-dienoate + NADP+ \rightleftharpoons --9alpha,15-dihydroxy-11-oxoprosta-5,13-dienoate + NADPH + H+...
(PGFS) catalyzes the formation of 9α,11β-PGF2α,β from PGD2 and PGF2α from PGH2 in the presence of NADPH. This enzyme has recently been crystallyzed in complex with PGD2 and bimatoprost (a synthetic analogue of PGF2α).
Function
There are currently ten known prostaglandin receptorProstaglandin receptor
There are currently ten known prostaglandin receptors on various cell types. Prostaglandins bind to a subfamily of cell surface seven-transmembrane receptors, G-protein-coupled receptors.These receptors are named:* DP1-2 - DP1, DP2 receptors...
s on various cell types. Prostaglandins ligate a sub-family of cell surface seven-transmembrane receptors, G-protein-coupled receptors. These receptors are termed DP1-2, EP1-4, FP, IP1-2, and TP, corresponding to the receptor that ligates the corresponding prostaglandin (e.g., DP1-2 receptors bind to PGD2).
The diversity of receptors means that prostaglandins act on an array of cells and have a wide variety of effects such as:
- cause constriction or dilation in vascular smooth muscleSmooth muscleSmooth muscle is an involuntary non-striated muscle. It is divided into two sub-groups; the single-unit and multiunit smooth muscle. Within single-unit smooth muscle tissues, the autonomic nervous system innervates a single cell within a sheet or bundle and the action potential is propagated by...
cells - cause aggregation or disaggregation of plateletPlateletPlatelets, or thrombocytes , are small,irregularly shaped clear cell fragments , 2–3 µm in diameter, which are derived from fragmentation of precursor megakaryocytes. The average lifespan of a platelet is normally just 5 to 9 days...
s - sensitize spinal neuronNeuronA neuron is an electrically excitable cell that processes and transmits information by electrical and chemical signaling. Chemical signaling occurs via synapses, specialized connections with other cells. Neurons connect to each other to form networks. Neurons are the core components of the nervous...
s to pain - induce labor
- decrease intraocular pressure
- regulate inflammatory mediation
- regulate calciumCalciumCalcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...
movement - control hormoneHormoneA hormone is a chemical released by a cell or a gland in one part of the body that sends out messages that affect cells in other parts of the organism. Only a small amount of hormone is required to alter cell metabolism. In essence, it is a chemical messenger that transports a signal from one...
regulation - control cell growthCell growthThe term cell growth is used in the contexts of cell development and cell division . When used in the context of cell division, it refers to growth of cell populations, where one cell grows and divides to produce two "daughter cells"...
- acts on thermoregulatory center of hypothalamusHypothalamusThe Hypothalamus is a portion of the brain that contains a number of small nuclei with a variety of functions...
to produce feverFeverFever is a common medical sign characterized by an elevation of temperature above the normal range of due to an increase in the body temperature regulatory set-point. This increase in set-point triggers increased muscle tone and shivering.As a person's temperature increases, there is, in... - acts on mesangial cells in the glomerulusGlomerulusA glomerulus is a capillary tuft that is involved in the first step of filtering blood to form urine.A glomerulus is surrounded by Bowman's capsule, the beginning component of nephrons in the vertebrate kidney. A glomerulus receives its blood supply from an afferent arteriole of the renal...
of the kidneyKidneyThe kidneys, organs with several functions, serve essential regulatory roles in most animals, including vertebrates and some invertebrates. They are essential in the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and...
to increase glomerular filtration rate
Prostaglandins are potent but have a short half-life before being inactivated and excreted. Therefore, they send only paracrine (locally active) or autocrine (acting on the same cell from which it is synthesized) signals.
Types
The following is a comparison of different types of prostaglandin, prostacyclin I2 (PGI2), prostaglandin E2 (PGE2), and prostaglandin F2α (PGF2α).
| Type | Receptor Prostaglandin receptor There are currently ten known prostaglandin receptors on various cell types. Prostaglandins bind to a subfamily of cell surface seven-transmembrane receptors, G-protein-coupled receptors.These receptors are named:* DP1-2 - DP1, DP2 receptors... |
Function |
|---|---|---|
| PGI2 | IP |
|
| PGE2 | EP1 |
Bronchoconstriction Bronchoconstriction is the constriction of the airways in the lungs due to the tightening of surrounding smooth muscle, with consequent coughing, wheezing, and shortness of breath. Bronchoconstriction can also be due to an accumulation of thick mucus.... Smooth muscle Smooth muscle is an involuntary non-striated muscle. It is divided into two sub-groups; the single-unit and multiunit smooth muscle. Within single-unit smooth muscle tissues, the autonomic nervous system innervates a single cell within a sheet or bundle and the action potential is propagated by... contraction |
| EP2 |
Bronchodilatation Bronchodilatation is the dilatation of the airways in the lungs due to the relaxation of surrounding smooth muscle. It is the opposite of bronchoconstriction.... Smooth muscle Smooth muscle is an involuntary non-striated muscle. It is divided into two sub-groups; the single-unit and multiunit smooth muscle. Within single-unit smooth muscle tissues, the autonomic nervous system innervates a single cell within a sheet or bundle and the action potential is propagated by... relaxation |
|
| EP3 |
Stomach The stomach is a muscular, hollow, dilated part of the alimentary canal which functions as an important organ of the digestive tract in some animals, including vertebrates, echinoderms, insects , and molluscs. It is involved in the second phase of digestion, following mastication .The stomach is... acid secretion Stomach The stomach is a muscular, hollow, dilated part of the alimentary canal which functions as an important organ of the digestive tract in some animals, including vertebrates, echinoderms, insects , and molluscs. It is involved in the second phase of digestion, following mastication .The stomach is... mucus Mucus In vertebrates, mucus is a slippery secretion produced by, and covering, mucous membranes. Mucous fluid is typically produced from mucous cells found in mucous glands. Mucous cells secrete products that are rich in glycoproteins and water. Mucous fluid may also originate from mixed glands, which... secretion Uterus The uterus or womb is a major female hormone-responsive reproductive sex organ of most mammals including humans. One end, the cervix, opens into the vagina, while the other is connected to one or both fallopian tubes, depending on the species... contraction (when pregnant) Smooth muscle Smooth muscle is an involuntary non-striated muscle. It is divided into two sub-groups; the single-unit and multiunit smooth muscle. Within single-unit smooth muscle tissues, the autonomic nervous system innervates a single cell within a sheet or bundle and the action potential is propagated by... contraction Lipolysis Lipolysis is the breakdown of lipids and involves the hydrolysis of triglycerides into free fatty acids followed by further degradation into acetyl units by beta oxidation. The process produces Ketones, which are found in large quantities in ketosis, a metabolic state that occurs when the liver... inhibition |
|
| Unspecified |
Hyperalgesia Hyperalgesia is an increased sensitivity to pain, which may be caused by damage to nociceptors or peripheral nerves. Temporary increased sensitivity to pain also occurs as part of sickness behavior, the evolved response to infection.-Types:... Fever Fever is a common medical sign characterized by an elevation of temperature above the normal range of due to an increase in the body temperature regulatory set-point. This increase in set-point triggers increased muscle tone and shivering.As a person's temperature increases, there is, in... |
|
| PGF2α | FP |
Uterus The uterus or womb is a major female hormone-responsive reproductive sex organ of most mammals including humans. One end, the cervix, opens into the vagina, while the other is connected to one or both fallopian tubes, depending on the species... contraction Bronchoconstriction Bronchoconstriction is the constriction of the airways in the lungs due to the tightening of surrounding smooth muscle, with consequent coughing, wheezing, and shortness of breath. Bronchoconstriction can also be due to an accumulation of thick mucus.... |
Inhibition
Examples of prostaglandin antagonists are:- NSAIDs (inhibit cyclooxygenase)
- Corticosteroids (inhibit phospholipase A2 production)
- COX-2 selective inhibitors or coxibs
- Cyclopentenone prostaglandins may play a role in inhibiting inflammationInflammationInflammation is part of the complex biological response of vascular tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. Inflammation is a protective attempt by the organism to remove the injurious stimuli and to initiate the healing process...
Clinical uses
Synthetic prostaglandins are used:- To induce childbirthChildbirthChildbirth is the culmination of a human pregnancy or gestation period with the birth of one or more newborn infants from a woman's uterus...
(parturition) or abortionAbortionAbortion is defined as the termination of pregnancy by the removal or expulsion from the uterus of a fetus or embryo prior to viability. An abortion can occur spontaneously, in which case it is usually called a miscarriage, or it can be purposely induced...
(PGE2 or PGF2, with or without mifepristoneMifepristoneMifepristone is a synthetic steroid compound used as a pharmaceutical. It is a progesterone receptor antagonist used as an abortifacient in the first months of pregnancy, and in smaller doses as an emergency contraceptive. During early trials, it was known as RU-38486 or simply RU-486, its...
, a progesterone antagonist); - To prevent closure of patent ductus arteriosusPatent ductus arteriosusPatent ductus arteriosus is a congenital disorder in the heart wherein a neonate's ductus arteriosus fails to close after birth. Early symptoms are uncommon, but in the first year of life include increased work of breathing and poor weight gain...
in newborns with particular cyanotic heart defectCyanotic heart defectA cyanotic heart defect is a group-type of congenital heart defects . The patient appears blue , due to deoxygenated blood bypassing the lungs and entering the systemic circulation...
s (PGE1) - To prevent and treat peptic ulcerPeptic ulcerA peptic ulcer, also known as PUD or peptic ulcer disease, is the most common ulcer of an area of the gastrointestinal tract that is usually acidic and thus extremely painful. It is defined as mucosal erosions equal to or greater than 0.5 cm...
s (PGE) - As a vasodilatorVasodilationVasodilation refers to the widening of blood vessels resulting from relaxation of smooth muscle cells within the vessel walls, particularly in the large arteries, smaller arterioles and large veins. The process is essentially the opposite of vasoconstriction, or the narrowing of blood vessels. When...
in severe Raynaud's phenomenonRaynaud's phenomenonIn medicine, Raynaud's phenomenon is a vasospastic disorder causing discoloration of the fingers, toes, and occasionally other areas. This condition can also cause nails to become brittle with longitudinal ridges. Named for French physician Maurice Raynaud , the phenomenon is believed to be the...
or ischemiaIschemiaIn medicine, ischemia is a restriction in blood supply, generally due to factors in the blood vessels, with resultant damage or dysfunction of tissue. It may also be spelled ischaemia or ischæmia...
of a limb - In pulmonary hypertensionPulmonary hypertensionIn medicine, pulmonary hypertension is an increase in blood pressure in the pulmonary artery, pulmonary vein, or pulmonary capillaries, together known as the lung vasculature, leading to shortness of breath, dizziness, fainting, and other symptoms, all of which are exacerbated by exertion...
- In treatment of glaucomaGlaucomaGlaucoma is an eye disorder in which the optic nerve suffers damage, permanently damaging vision in the affected eye and progressing to complete blindness if untreated. It is often, but not always, associated with increased pressure of the fluid in the eye...
(as in bimatoprostBimatoprostBimatoprost is a prostaglandin analog/prodrug used topically to control the progression of glaucoma and in the management of ocular hypertension. It reduces intraocular pressure by increasing the outflow of aqueous fluid from the eyes...
ophthalmic solution, a synthetic prostamide analog with ocular hypotensive activity) - To treat erectile dysfunctionErectile dysfunctionErectile dysfunction is sexual dysfunction characterized by the inability to develop or maintain an erection of the penis during sexual performance....
or in penile rehabilitation following surgery (PGE1 as alprostadilAlprostadilProstaglandin E1 , known pharmaceutically as alprostadil, is a prostaglandin. It is a drug used in the treatment of erectile dysfunction and has vasodilatory properties.-Sexual dysfunction:...
). - To treat egg bindingEgg boundIn farming, aviculture and animal husbandry, the term egg binding refers to a medical condition in birds where the female is unable to pass an egg that has formed. The egg may be stuck near the cloaca, or further inside. Egg binding is a reasonably common, and potentially serious, condition that...
in small birds - As an ingredient in eyelashEyelashAn eyelash or simply lash is one of the hairs that grow at the edge of the eyelid. Eyelashes protect the eye from debris and perform some of the same function as whiskers do on a cat or a mouse in the sense that they are sensitive to being touched, thus providing a warning that an object is near...
and eyebrowEyebrowThe eyebrow is an area of thick, delicate hairs above the eye that follows the shape of the lower margin of the brow ridges of some mammals. Their main function is to prevent sweat, water, and other debris from falling down into the eye socket, but they are also important to human communication and...
growth beauty products due to side effects associated with increased hair growth