Trimethylsilyl group migration in the mass spectra of trimethylsilyl ethers of cholesterol oxidation products. product ion characterization by linked-scan tandem mass spectrometry.

Loss of the A ring in the electron-impact mass spectra of the trimethylsilyl (TMS) derivatives of several cholesterol oxidation products is accompanied by intramolecular migration of the 3-O-TMS group to the charge-retaining portion of the molecule. Linked-scan techniques (B/E and B(2)/E) were used to establish the fragmentation processes leading to the formation of the rearrangement ion. The TMS group appears to migrate to heteroatomic sites in the 5-; 6-, or 7-positions of the B ring. This structural assignment is supported by isotopic labeling studies and collision-induced dissociation of the resulting product ion.

Trirhabda canadensis (Coleoptera: Chrysomelidae) responses to plant odors.

The responses of the goldenrod leaf beetleTrirhabda canadensis to host and nonhost volatile odors were tested in a Y-tube olfactometer in the laboratory. Beetles preferred host to nonhost odors and were sensitive to concentrations of host odor. Beetles distinguished between host and nonhost volatiles of only one of the two nonhostSolidago species; host volatiles were preferred to all nonhost volatiles at the family and order levels. In other words, all nonhosts above the genus level had similar effects on beetle responses. Although the odors of most nonhosts were neutral (i.e., neither attractive nor repellent) to the beetles as tested against air, this neutrality disappeared if the odors of two or more nonhosts were added to the host odor and beetles were given a choice between this mixture and pure host odor. Given this choice, they strongly preferred pure host odor, which suggests that diversity of odors per se is unattractive to the beetles. Beetles walked rather than flew to locate their hosts in the field, and their movements suggest that they used olfactory cues to locate hosts.

Hydroxylation of [3H]5 alpha-androstane-3 beta,17 beta-diol by whole tissue, epithelial cells and fibroblasts from the same hyperplastic human prostate.

Hydroxylations of 3 beta-hydroxy 5 alpha-dihydro C19-steroids are terminal reactions by which male accessory sex organs dispose of intracellular androgens. Cellular androgen egress is of particular interest in benign prostatic hyperplasia (BPH) where the elevated nuclear 5 alpha-dihydrotestosterone-receptor content may be implicated in the etiology of the disease. We here report substitution of hydroxyl groups at C-6 alpha, C-7 beta and predominantly at C-7 alpha of [3H]5 alpha-androstane-3 beta,17 beta-diol on incubation of 3 and 8.5 nM substrate concentrations with minced and explanted human BPH tissue. Fibroblasts isolated from the same prostatectomy specimen hydroxylated 3 nM radiosubstrate mainly at C-6 alpha, with extensive metabolism to 17-oxosteroids. Epithelial cells from the same tissue source substituted to the same extent at the three positions. Competing 3 beta-hydroxysteroid dehydrogenase exceeded hydroxylase activity only in epithelial-cell cultures. Our findings support previous evidence that prostatic epithelial and stromal cells make different contributions to androgen disposition by the 3 beta-hydroxysteroid pathway.

Metabolism of radiotestosterone to 3 beta,6 alpha- and 3 beta,7 alpha-dihydroxy 5 alpha-steroids by rat ventral, canine and human prostate in organ culture.

We report here the structural assignment for the hydroxylated 5 alpha-reduced metabolites in the culture medium following incubation of radiolabelled testosterone with explants of rat ventral prostate, canine cauda epididymidis and prostate, and benign hyperplastic canine and human prostate. Explants were incubated for 21 h at 37 degrees C in surface contact with serum-free Trowell's T8 medium containing 1.7 microM or 8.5 nM substrate. After uptake determination, radiosteroid patterns in explants and media were obtained by t.l.c. The C19O3-metabolites released into the culture medium were resolved by h.p.l.c. and fractions migrating with appropriate reference compounds were crystallized to constant SA with carriers synthesized for this purpose. 5 alpha-Androstane-3 beta,6 alpha,17 beta-triol and 3 beta,6 alpha-dihydroxy-5 alpha-androstan-17-one were identified as the major C19O3-radiometabolites of rat ventral prostate. In the culture medium of canine prostate and epididymis and human prostate, 5 alpha-androstane-3 beta,7 alpha,17 beta-triol and 3 beta,7 alpha-dihydroxy 5 alpha-androstan-17-one were the principal hydroxylation products, with 6 alpha-hydroxy epimers as significant minor products of the canine prostate and epididymis and 5 alpha-androstane-3 beta,7 beta,17 beta-triol as a significant minor radiometabolite of human prostate tissue. Treatment of the castrated dog with androgen and estrogen causes an oxidative shift to striking predominance of 3 beta,7 alpha-dihydroxy 5 alpha-androstan-17-one. The 3 beta-hydroxy-5 alpha-androstane configuration of the identified C19O3-metabolites supports a pathway of prostatic and epididymal testosterone disposition which effects activation by 5 alpha-reductase and inactivation and egress by the coupled 5 alpha-3-oxosteroid reductase/3 beta-hydroxysteroid hydroxylase reactions.

Angiotoxicity of oxygenated sterols and possible precursors.

Cell death, inflammation, and repair in rabbits' aortas and pulmonary arteries were observed at 3-, 7-, and 10-day periods after the intravenous injection of oxygenated sterols. Thus, oxygenated sterols, not cholesterol, may play the primary role in arterial wall injury and lesion development.

Antitumor plants. IV. Constituents of Simarouba versicolor.

beta-Sitosterol, epilupeo, amarolide-11-acetate, amarolide-2,11-diacetate, ailanthinone and glaucarubinone have been isolated from S. versicolor. The cytotoxic and antileukemic activities of extracts of this plant are due chiefly to glaucarubinone.