Summary. Enzymes liberated by growing der‐matophytes are of pathogenetic importance in tinea. To investigate the influence of nutrients on this enzyme release, Trichophyton rubrum was grown in media containing peptone, keratin and lipids, to which glucose was added in separate assays. The culture supernatants were compared for extracellular enzyme activities by use of the api‐zym® test. Our results clearly show that the extracellular enzyme activity is dependent on the nutrients supplied. Seven different enzymes were released when keratin was supplied, as compared with only five and two respectively when lipids or peptone were available. Among these enzymes alkaline phosphatase and N‐acetyl‐β‐glucosaminidase were detected in all cultures lacking glucose. Enzyme release was inhibited completely when glucose was added to the media, except for N‐acetyl‐β‐glucosaminidase in peptone cultures. This dependency of enzyme release on fungal nutrition can be expected to occur in vivo too. In addition, it has to be considered for in vitro cultural conditions. Alkaline phosphatase and acetylglucosaminidase may be more important in tinea than has been assumed so far. Zusammenfassung. Von Dermatophyten frei‐gesetzte Enzyme sind bei der Entstehung einer Tinea pathogenetisch relevant. Um den Einfluβ von Nährsubstraten auf die Enzymfreisetzung von Trichophyton rubrum zu untersuchen, wurde dieser Erreger in pepton‐, keratin‐ und lipid‐haltigen Nährmedien gezüchtet, denen in zusätz‐lichen Ansätzen Glucose beigefügt wurde. Die Kulturüberstände wurden mit dem api‐zym® ‐Test auf extrazelluläre Enzymaktivität unter‐sucht. Unsere Ergebnisse zeigen eine eindeutige Abhängigkeit dieser Enzymaktivitäten vom Nährstoffangebot. Bei Wachstum auf Keratin wurden sieben verschiedene Enzyme bestimmt, bei Lipid‐ bzw. Peptonangebot dagegen nur fünf bzw. zwei. Alkalische Phosphatase und N‐Acetyl‐β‐Glucosaminidase waren in alien glucosefreien Nährmedien nachweisbar. Durch Glucosezusatz zu den Nährmedien erfolgte eine vollständige Hemmung der Enzymfreisetzung mit Ausnahme von N‐Acetyl‐β‐Glucosaminidase in der Pepton‐kultur. Diese Nährstoffabhangigkeit der Enzymfreisetzung kann auch in vivo vermutet werden und ist bei der Auswahl von Kulturmedien zu berücksichtigen. Alkalische Phosphatase und Acetylglucosaminidase könnten mehr Bedeutung bei Dermatophytosen besitzen als bisher ange‐nommen.

The influence of the pH of the incubation medium on the cellular accumulation of tritiated fentanyl, lofentanil, and alfentanil was investigated in isolated guinea pig atria. Fentanyl and lofentanil accumulated in atrial tissue up to about 30- and 50-fold, respectively. The amount of drug bound when equilibrium was attained was found to be dependent upon the pH of the medium. By plotting binding equilibria v. pH of the bath, curves were obtained which resembled titration curves. Half-maximal binding was attained at pH values close to the pKa values of fentanyl and lofentanil. Alfentanil was found to accumulate less. The uptake by the tissue was strongly proportional to the extracellular concentration. Atria equilibrated with fentanyl at pH 8.5 released the compound rapidly when exposed to a pH of 7.0, even in the continuous presence of fentanyl in the bath. The consequences of the findings for in vivo conditions are discussed with respect to a possible augmentation of the actions of fentanyl by respiratory acidosis.