Determination of glycogen and enzymes of glycogen metabolism in human hair follicles.

The skin epithelium and its organelles use glycogen as well as glucose as source of energy. Therefore the characterisation of glycogen metabolism and the enzymes involved is important in the study of mechanisms regulating the normal or abnormal differentiation of skin organelles such as sebaceous glands and hair follicles. The present paper describes fluorimetric methods for the determination of glycogen and for the measurements of phosphorylase and phosphorylase kinase activity in one and the same lysate of minute tissue samples. The methods were tested for their suitability on freshly isolated human hair follicles and cultured hair follicle cells. The possible use of these techniques for studies on the pathophysiology of acne and hirsutism is discussed.

Formation of mercapturic acids from acrylonitrile, crotononitrile, and cinnamonitrile by direct conjugation and via an intermediate oxidation process.

After administration of acrylonitrile, crotononitrile and cinnamonitrile to rats, two types of mercapturic acids were isolated from urine and identified by mass and NMR spectroscopy as N-acetyl-S-(2-cyanoethyl)-L-cysteine (I) and N-acetyl-S-(2-hydroxyethyl)-L-cysteine (II) (methyl-substituted in the case of crotonitrile and phenyl-substituted in the case of cinnamonitrile). After pretreatment of rats with the cytochrome P-450 inhibitor 1-phenylimidazole, no trace of mercapturic acid II was found, whereas a higher amount of mercapturic acid I was excreted. It is suggested that the first type of products result from direct addition of glutathione, whereas the second group of metabolites (II), in which the cyano group has been replaced by a hydroxyl group, are formed via an intermediate epoxide. Substituents on the double bond had a considerable influence on the ratio of the two mercapturic acids formed, and thus presumably on the amount metabolized via an oxidative process: the ratio of the cyano (I) to hydroxy (II) mercapturic acid was 72:28 for AN; introduction of a methyl or a phenyl group resulted in ratios of 91:9 and 98:2, respectively.