Properties of the ultraviolet-absorbing lipids produced by rat adrenals in vitro

Abstract

Ultraviolet-absorbing lipids produced by incubated rat adrenals were separated by paper chromatography in toluene-propylene glycol, and some physical, chemical and biological properties were examined. Lipids with chromatographic mobility, absorption spectra in methanol and in sulphuric acid and with the reducing power of corticosterone, aldosterone, 11-dehydrocorticosterone and 11-deoxycorticosterone were recovered. No evidence was found for the production of lipids with a dihydroxyacetone side chain, of 17-oxo steroids and of 17-oxogenic steroids. A non-reducing Porter-Silber chromogen was recovered with a polarity slightly greater than that of 11-deoxy-17-hydroxycorti-costerone and with maximum absorption in methanol at 240 m[mu] and in sulphuric acid at 290 m[mu]. Acetylation of this material yielded two components, with RF values 0.5 and 0.9 in benzene-formamide; other properties were the same as those of the parent compound. The lipid with the mobility of cortisol in toluene-propylene glycol had properties expected of a [DELTA]4-3-ketone, did not reduce tetrazolium and its spectrum in sulphuric acid differed from those of both isomers of pregn-4-ene-11[beta]:(20):21-triol-3-one. Upon acetylation, products of low polarity in benzene-formamide were obtained. A dose of 0.1 [mu]g of lipid with the mobility of aldosterone depressed the urinary ratio of sodium to potassium in the rat by the same amount as 3 [mu]g of deoxycorticosterone acetate. The Porter-Silber chromogen gave variable results and the lipid with the mobility of corticosterone was inactive. In the eosinopenia assay the Porter-Silber chromogen was inactive at a dose of 25 [alpha]g/rat. A similar dose of the lipid with the mobility of corticosterone was one-third as active as cortisone. The production of the Porter-Silber chromogen and of the lipid with the properties of corticosterone was greatly enhanced by adrenocorticotropic hormone and by factors increasing the response to adrenocorticotropic hormone, such as calcium, inosine and glucose. The effect on the other lipids was small or absent.