| uterine relaxing factor | <protein> Polypeptide hormone produced by corpus luteum and found in the blood of pregnant animals. Acts, as its name suggests, to cause muscle relaxation during parturition. Human relaxin has an A chain of 24 amino acids and a B chain of 29. Has structural similarity to insulin. (18 Nov 1997) |
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| filtrate factor | Former term for pantothenic acid. (05 Mar 2000) |
| Fitzgerald factor | high molecular weight kininogen |
| Flaujeac factor | high molecular weight kininogen |
| Fletcher factor | <chemical> A plasma protein which is the precursor of kallikrein. Plasma that is deficient in prekallikrein has been found to be abnormal in thromboplastin formation, kinin generation, evolution of a permeability globulin, and plasmin formation. The absence of prekallikrein in plasma leads to fletcher factor deficiency, a congenital disease. Chemical name: Kallikreinogen (12 Dec 1998) |
| labile factor | <chemical> Heat- and storage-labile plasma glycoprotein which accelerates the conversion of prothrombin to thrombin in blood coagulation. Factor v accomplishes this by forming a complex with factor xa, phospholipid, and calcium (prothrombinase complex). Deficiency of factor v leads to owren's disease. Chemical name: Blood-coagulation factor V (12 Dec 1998) |
| Lactobacillus bulgaricus factor | <chemical> 2,4-dihydroxy-n-[2-[(2-merceptoethyl)carbamoyl]ethyl]-3,3-dimethylbutyramide. An intermediate in the pathway of coenzyme a formation in mammalian liver and some microorganisms. Chemical name: Butanamide, 2,4-dihydroxy-N-(3-((2-mercaptoethyl)amino)-3-oxopropyl)-3,3-dimethyl-, (R)- (12 Dec 1998) |
| Lactobacillus casei factor | <biochemistry> Pteridine derivative that is abundant in liver and green plants and is a growth factor for some bacteria. The biochemically active form is tetrahydrofolate (see folate). (12 Nov 1997) |
| lactogenic factor | <protein> Pituitary lactogenic hormone (23 kD) Synthesised on endoplasmic reticulum bound ribosomes as preprolactin that has an N terminal signal peptide that is cleaved from the mature form. The conversion of preprolactin to prolactin has been much used as an assay for membrane insertion. (18 Nov 1997) |
| Laki-Lorand factor | <chemical> Fibrin stabilizing factor. It is a glycoprotein activated by thrombin in the presence of calcium to form factor xiiia. Factor xiii is found evenly distributed between plasma and platelets. Its function is to stabilise the formation of the fibrin polymer (clot) which culminates the coagulation cascade. Chemical name: Blood-coagulation factor XIII (12 Dec 1998) |
| follicle-stimulating hormone-releasing factor | A decapeptide of hypothalamic origin capable of accelerating pituitary secretion of follitropin. Synonym: follicle-stimulating hormone-releasing factor, follicle-stimulating hormone-releasing hormone. Origin: follicle-stimulating hormone + L. Libero, to free, + -in (05 Mar 2000) |
| lethal factor | A disorder that prevents effective reproduction by those affected; e.g., Klinefelter syndrome. (05 Mar 2000) |
| Leukaemia inhibitory factor | <growth factor> Polypeptide growth factor or cytokine with wide range of activities. Regulates growth and differentiation of primordial germ cells and embryonic stem cells but has effects on peripheral neurons, osteoblasts, adipocytes and various cells of the myeloid lineage. Given to adult animals induces weight loss, behavioural disorders and bone abnormalities. Many of the effects of LIF in vitro can be mimicked by IL-6, oncostatin M and ciliary neurotrophic factor, all of which interact indirectly with gp130, a shared tranducer subunit. (18 Nov 1997) |
| leukocytosis-promoting factor | A substance obtained by Menkin from inflammatory exudates; it stimulates leukocytosis. (05 Mar 2000) |
| leukopenic factor | A principle obtained by Menkin from inflammatory exudates; it causes leukopenia when injected into normal animals. (05 Mar 2000) |