From Big Medical Encyclopedia

RELAKSIN — biologically active agent, the hypothetical hormone produced by a yellow body and providing during pregnancy and childbirth stretching and a softening of a pubic symphysis (a pubic joint) and ligaments of a sacroiliac joint (an ieosacral joint) and also expansion of the channel of a neck of uterus.

The ruble was for the first time described in 1926 Mr. of F. L. Hisaw, to-ry found out that extract from a yellow body of an ovary of a Guinea pig after full extraction of progesterone has the listed specific properties. By extraction of the fat-free yellow bodies of Guinea pigs of 2% solution salt to - you and processings of the received extract ammonium sulfate were received drug P.; 1 units biol. to R.'s activity there corresponds 1 mg of the drug containing 15% of nitrogen. Drug P. even in large numbers has no activity of progesterone and oestrogenic activity, i.e. is in biol. relation independent substance.

The chemical structure of R. is established in 1977 represents protein about a pier. it is powerful (weighing) 6000. Its molecule consists of two peptide chains: chains And, constructed of 22 amino-acid remains, and the chain In constructed of 30 amino-acid remains. Peptide chains in a molecule P. are connected with each other two S — S-bonds (disulfide bridges). We will poorly dissolve the river in water and in 95% alcohol, we will not dissolve in organic solvents, the isoelectric point is at pH 5,4 — 5,5. Biol. activity of the received drugs P. decreased under the influence of oxidizers and proteases (pepsin, trypsin). At storage within a year biol. activity of drugs P. practically did not change.

The ruble is found in blood of pregnant females of animal different types, in blood of pregnant women, in extracts from a placenta, but not found at the castrated gisterektomirovanny females, and also at males. From blood of females of experimental animal (doe-rabbits) R. disappeared during 3 — 7 days after the delivery.

Did not find practical application in R.'s medicine yet.

See also Yellow body .

Bibliography: Abramowitz A. And. and. lake of Preparation, biological assay and properties of relaxin, Endocrinology, v. 34, p. 103, 1944; Hisaw F. L. a. o. importance of the female reproductive tract in the formation of relaxin, ibid., p. 122; M a r d e r S. N. a. Money W. L. Concentration of relaxin in the blood serum of pregnant and postpartum rabbits, ibid., p. 115.

H. A. Zarubina.