In the experimental infection of Cryptococcus neoformans M1 strain against the albino rats weighing 80 to 90 grams, morbidity, quantitative reduction culture from the various organs, histopathologic studies and 17-OHCS measurement in 24-hour urine were carried out. The retults were as follows:
1. The rats administered prednisolone only showed an increased C/F ratio (conjugated urinary 17-OHCS/ free urinary 17-OHCS) in proportion to the period of administraion in case the rats were given prednisolone at a dosis of 50μg. This suggested that prednisolone administered abunduntly becomes conjugated in the body rather than remains free. In contrast the rats given prednisolone at a dosis of 0.5μg showed the same C/F value with normal rats.
2. The unfavorable effects of adrenal corticoids on fungal infections were shown by changes of C/F, morbibity and the results obtained by reduction culture. These effects of adrenal corticoids were influenced neither by the quantity of administered prednisolone nor the time of administration.
3. The effectiveness of antifungal antibiotics on experimental cryptococcosis was determined by the day of initial death, morbidity, C/F ratio and the results obtained by reduction culture. The useful antifungal antibiotics were Amphotericin B, Trichomycin and Nystatin in a descending order of effectiveness.
4. In the experiment in which both. prednisolone and antifungal antibiotics were adminstered, the effects of antifungal antibiotics, even if they were strong enough, were diminished by the simultaneous administration of prednisolone.
5. Prednisolone was found to produce the cystic lesion in experimental cyptococcosis, while the addition of antifungal antibiotics reduced the lesion and induced the intense granulomatous changes. In this experiment, the useful antifungal antibiotics were Amphotericin B, Trichomycin and Nystatin in a descending order of effectiveness.