The Radiochemical Centre Limited

Reginald Monks

Anthony Leonard Riley

Virginia Edith Chambers

Russell James Bayly

Gavin Murray Cree

Idris Lewis Thomas

Novel compounds having the formula (II) ##STR1## where X is radioactive Se or Te, z is 0 or 1 and R is OH or an amino acid residue, particularly 23-[.sup.75 Se]-selena-25-homocholic acid and its glycine and taurine conjugate have outstandingly good properties for the investigation of bowel function.

Bile acids

Body function of a mammal is investigated using a .gamma.-emitting .sup.75 Se or .sup.123m Te labelled derivative of a bile acid or bile salt. Thus bowel function may be investigated by oral administration of the labelled compound followed, after a suitable period of time, by either a whole body count or a faecal count of radioactivity. Preferred bile acids and salts are substituted either at the 19-position or in the C-17 side chain.

Investigating body function

The present invention provides compounds having the general formula ##STR1## wherein R is ##STR2## and A is 0 or 1,

Labelled bile acids

Folic acid and related compounds are assayed by competitive radio-assay using a selenium - 75 labelled version of folic acid as the competing compound.

Saturation analysis of folate compound with selenium-75 labeled folate

Novel selenium derivatives of steroids have the formula I, ##STR1## where X is hydrogen or acyl, Y is hydrocarbon and n is 0 or 1, preferably 0. Such compounds, labelled with selenium-75 are of use for investigating body function, particularly for imaging the adrenal glands, and are claimed superior for the purpose to the 6.beta.- and 19- iodine derivatives of cholesterol.

Organ visualization

New selenium-75 labelled derivatives of cyclic nucleotides are described, which are of value in the saturation analysis of cyclic nucleotides, particularly adenosine-3', 5'-cyclic monophosphate (cyclic AMP) in body fluids.

Selenium labelled compounds in the saturation analysis of cyclic

The invention provides a method and a kit for the saturation analysis of a steroid characterized by the use of a selenium-75 labelled version of the steroid to be assayed. Selenium-75 derivatives of steroids are quite simple to prepare and have practical advantages over other radioactively labelled steroids. Lists of derivatives and examples of competitive radio-assays are given.

Saturation analysis

Novel selenium-75 derivatives of cholesterol have the formula ##STR1## (I) where X is hydrogen or acyl, Y is alkyl and n is 0 or 1. They are useful for visualizing the adrenal glands of mammals.

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Amersham, United Kingdom

Reginald Monks