Oral contraceptive steroids increased the residence time of caffeine in 9 young women by a factor of 2. The effect was already manifested during the first cycle 2 weeks after starting oral contraceptive steroids (OCS) and was slightly increased in the second cycle, after 6 weeks on OCS. Toxic effects attributed to oral contraceptive steroids may in part be indirect and due to prolonged retention of absorbed toxic agents to which women are exposed.

This work was supported in part by grants from the Netherlands' Organization for the Advancement of Pure Research (Z.W.O.) and from the Ministry of Health.

No abstract

Neutral cannabinoids with a pentyl side chain-for example, cannabidiol, tetrahydrocannabinol, and cannabinol-are generally accompanied by homologs with a propyl side chain, of which at least one has psychotropic activity. Samples of hashish and marihuana from Asia especially sometimes have abundant amounts of propyl cannabinoids, the quantities being of the same order as that of the accompanying pentyl cannabinoids. Detection and identification of the propyl and pentyl cannabinoids in gas chromatography and thin-layer chromatography is discussed.

B i j d z i k x e w i c z , R. T. A i .p i n , D. A. L i g h t n e r , C. D j e r a s s i , R. M e c h o u l a m a n d Y. G a o n i , Tetrahedron, 21 (1965) 1881. 2 U. C l a u s s e n a n d F.