Corticosterone impairs the mRNA expression and activity of 3beta- and 17beta-hydroxysteroid dehydrogenases in adult rat Leydig cells.

Clinical and experimental studies, including our own observations, have shown the adverse effects of excess glucocorticoids on testicular steroid hormone production. The present study was designed to gain insight into the molecular mechanisms by which excess corticosterone impairs Leydig cell steroidogenesis. To achieve this, adult rats were administered with corticosterone-21-acetate (2 mg/100 g body weight) twice daily for 15 days.

Effects of excess corticosterone on NADPH generating enzymes and glucose oxidation in Leydig cells of adult rats.

Clinical and experimental studies have shown the adverse effects of excess glucocorticoid on testicular testosterone production. The NADPH co-enzyme has been recognized as an important factor that regulates several steps in steroidogenesis, while glucose oxidation acts as a limiting factor on testicular testosterone production. Nevertheless, the impact of excess corticosterone, the stress hormone on testicular NADPH availability and glucose oxidation is unknown.

Pauli principle and chaos in a magnetized disk.

We present results of a detailed quantum-mechanical study of a gas of N noninteracting electrons confined to a circular boundary and subject to homogeneous dc plus ac magnetic fields [B=B(dc)+B(ac)f(t), with f(t+2pi/omega(0))=f(t)]. We earlier found a one-particle classical phase diagram of the (scaled) Larmor frequency omega;(c)=omega(c)/omega(0) vs epsilon=B(ac)/B(dc) that separates regular from chaotic regimes. We also showed that the quantum spectrum statistics changed from Poisson to Gaussian orthogonal ensembles in the transition from classically integrable to chaotic dynamics.