Gonadotropic substances

Gurin has tabulated data from an examination of gonadotropic substances derived from several sources. The luteinizing hormone and the F. S. H. from the pituitary are stated to contain D-mannose and 

Rimington and Rowlands have isolated an extremely active preparation from the serum of pregnant mares. This material was obtained in a high degree of purity and was shown to contain hexose and hexosamine in the molar ratio of 2/1. In the fractionation it appeared that, at first, the hexose content decreases as the potency is raised, but later this trend is reversed. It was shown that hexose content could not be taken as indication of gonadotropic activity. The hexose/hexosamine ratio was 2/1 as in normal serum mucoproteins, so that this gonadotropic hormone may be a modified serum mucoprotein. 

The thyreotropic hormone from pituitary extracts appeared to be an entity separate from the luteinizing hormone and contained nitrogen, 13% carbohydrate, 3.5% and D-glucosamine, 2.5%. 

Further work both on the protein and carbohydrate constituents is awaited with interest, for it has been shown by Evans and Hauschildt that the activity of the hormone of pregnant mares serum is a function of the whole molecule, inasmuch as it is destroyed both by proteolytic and carbohydrate-splitting enzymes. 

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Krasovskii, G.N., S.P. Varshavskaya, and A.l. Borisov. 1976. Toxic and gonadotropic effects of cadmium and boron relative to standards for these substances in drinking water. Environ. Health Perspect. 13 69-75. 

Various other substances have been shown to act as inhibitors of pituitary gonadotropic activity. These include synthetic arginine vasotocin (M13) and an extract prepared from the pineal gland of cattle (R14). 

For development of preventive measures for work-related reproductive health disorders, pathology of a fetus and newborn, it is expedient to examine a degree of hazard for health depending on character of action of chemical substances because they can produce the gonadotropic and embriotropic effects, etc. Thus it is necessary to take into account standard indices or so-called phrases of risk (R-phrase) for chemical substances (EU Directive 92/32/EEC). To mark the chemicals with specific kind of action in European Union they apply the R-phrases for classification. Such designation of chemical substances helps to receive information on reproductive risks for the substances used on workplaces. 

G. are essential components of receptors for virus and plant agglutinins, and of blood group substances The siderophilins and ceruloplasmin are G.Some G. are membrane carrier proteins The carbohydrate portion of gonadotropic hormones is essential to their biological activity in many cases, selective removal of the terminal sialic acid residues inactivates the hormone. The carbohydrate evidently serves as a label for recognition by a receptor. 

VI. Is THE Activity of the Gonadotropic Hormone Due to the Substance in Its Original Form ... 

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