Qualitative analysis by gas chromatography-mass spectrometry (GC-MS) of the auxins present in the root, cotyledons and epicotyl of 3-dold etiolated pea (Pisum sativum L., cv. Alaska) seedlings has shown that all three organs contain phenylacetic acid (PAA), 3-indoleacetic acid (IAA) and 4-chloro-3-indoleacetic acid (4Cl-IAA). In addition, 3-indolepropionic acid (IPA) was present in the root and 3-indolebutyric acid (IBA) was detected in both root and epicotyl. Phenylacetic acid, IAA and IPA were measured quantitatively in the three organs by GC-MS-single ion monitoring, using deuterated internal standards. Levels of IAA were found to range from 13 to 115 pmol g(-1) FW, while amounts of PAA were considerably higher (347-451 pmol g(-1) FW) and the level of IPA was quite low (5 pmol g(-1) FW). On a molar basis the PAA:IAA ratio in the whole seedling was approx. 15:1.

Experientia 40 (1984), Birkhfiuser Verlag, CH-5010 Basel/Switzerland 549 lite of DHA, fr. 5, was in addition recrystallized to constant isotope ratio (table 2). In all 30-min DHA incubations carried out either without cofactors or with NADP the main metabolite was androstenedione. The utilization of the substrate by A53/~HSD was increased when NADP was added in both experimental groups. The recovery of androstenedione, however, was higher in the incubations performed during breeding, suggesting increased A 53flHSD activity in the testicular tissue of these animals. When the incubation time was doubled to 1 h and NADP/ NADPH added in equimolar concentrations, testosterone was found as the main metabolite of DHA during breeding but not after breeding.Comparable observations were made when androstenedione was used as the substrate. In the 1-h incubations with NADP/ NADPH testosterone was produced in the same proportions as in DHA incubations and the production declined similarly after breeding. These observations suggest that the activity of 17flHSD may be regulated for the needs of testicular androgen production leading to the increased testosterone formation during breeding. Previous studies in other urodele Amphibia (Pleurodeles waltlii, Triturus cristatus carnifex) have also demonstrated that testosterone is the major androgen produced in vitro by the testis 2, 3. In peripheral plasma of Ambystoma tigrinum, Pseudoeyrycea smithi12 Necturus maculosus ~3 5a-DHT can be found in relatively minor amounts compared to testosterone. In accordance with these findings 5a-or 5fl-DHT were not found in our studies. On the other hand testicular tissue of anuran species has been found to form large amounts of 5a-DHT from exogenous precursors during breeding 1,4,6,7. This ability differs therefore from that observed in urodele Amphibia and among all other orders of vertebrates 6,~4. In conclusion the formation of biologically active androgens from DHA and androstenedione in testicular homogenates of T. vulgaris showed a clearcut variation between breeding, aquatic newts and non-breeding, terrestrial newts. The difference was most distinct in relation to 17flHSD activity. Testosterone was quantitatively the most important metabolite of both substrates during breeding.Summary. The concentrations of fl-phenylethylamine, p-tyramine, m-tyramine, m-octopamine and tryptamine in the ganglia or foot muscle of Helix aspersa range from < 0.6 to 11 ng/g. p-Octopamine levels are higher in ganglia (327 ng/g) than in foot muscle (4.1 ng/g). Dopamine and 5-hydroxytryptamine range from 840 to 2710 ng/g while their acid metabolites, 3, 4-dihydroxyphenylacetic acid, 3-methoxy-4-hydroxyphenylacetic acid and 5-hydroxyindoleacetic acid range from < 20 to 130 ng/g. It has been known for quite some time that the ganglia of gastropods contain relatively high concentrations of dopamine (DA) or 5-hydroxytryptamine (5-HT) 3 5, and this has been confirmed by a histochemical fluorescence technique 6. In addition, snail ganglia contain relatively large concen...

Reduction of the methylene blue cation during fast atom bombardment was studied in glycerol-thioglycerol and glycerol-nitrobenzyl alcohol matrices. The relative abundances of reduced species are significantly lower in a matrix containing 0.2 m thioglycerol in glycerol than they are in pure thioglycerol. Pure 3-nitrobenzyl alcohol or a glycerol-nitrobenzyl alcohol mixture is a less effective matrix material. These results are discussed in terms of a postulated mechanism for the formation of the reduced dye cation species.

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The enhancement of the (C + 1)/C ratio in the fast atom bombardment mass spectra of seven pyridinium cations has been measured. No dependence of the enhancement on the cation reduction potential could be identified. The N-methyl pyridinium cation, which showed no enchancement under matrix-free conditions, exhibited an increase in the (C + l)/Cratio with decreasing concentration. This concentration dependence was eliminated when the bombardment energy was reduced from 9 to 5 keV. Possible mechanisms for the concentration dependence and the variation with bombardment energy are proposed.