METHOD: In a randomized, double-blind, two-period crossover study, pantoprazole 
40 mg or placebo were given orally to 12 male volunteers for 2 weeks each. There 
was a wash-out period of at least 1 week between the two treatment periods. The 
effects of pantoprazole or placebo on cortisol and testosterone (primary 
criteria), and tri-iodothyronine, thyroxine, thyroid-stimulating hormone, 
thyronine-binding protein, parathyroid hormone, insulin, glucagon, renin, 
aldosterone, follicle-stimulating hormone, luteotrophic hormone, prolactin and 
somatotrophic hormone were compared. In addition, intragastric 24-h pH, 24-h 
H(+)-activity, and volume of nocturnal gastric juice were determined by gastric 
aspiration technique.
RESULTS: Pantoprazole did not influence plasma levels of testosterone, circadian 
cortisol concentrations or plasma cortisol levels after exogenous 
adrenocorticotropic hormone stimulation, as compared to placebo (P > 0.05, 
Koch's test). Furthermore, there were no clinically relevant changes with any of 
the other endocrine parameters. Pantoprazole significantly increased the median 
24-h pH (group median 4.3 vs. 1.8; P < 0.001) and decreased 24-h H(+)-activity 
(4.0 vs. 22.6 mmol/L; P < 0.001). The volume of nocturnal gastric juice did not 
significantly differ between the two treatments. Pantoprazole was well tolerated 
and the frequency of adverse events was similar to placebo. No drug-related 
changes in laboratory values were observed.
CONCLUSION: Pantoprazole did not influence endocrine function in healthy male 
volunteers during short-term treatment.