Influence of gender on prednisolone effects on whole blood T-cell deactivation and trafficking in rats

J Pharm Sci. 1999 Jan;88(1):46-51. doi: 10.1021/js9802695.


Prednisolone (5 mg/kg intravenous) was administered to adrenalectomized male and female Sprague-Dawley rats (250-350 g) to assess the effects of gender on disposition and pharmacoimmunodynamics. Plasma concentrations of prednisolone were determined by high-performance liquid chromatography. Incorporation of [3H]thymidine (3H-TDR) was used to determine whole blood T-cell (WBTC) trafficking and deactivation following stimulation with Concanavalin-A. Whole blood T-cell trafficking was determined indirectly by using the glucocorticoid receptor antagonist RU-40555 (250 ng/mL) added to ex vivo cultures of whole blood from animals dosed with prednisolone. Mean (+/- SD) prednisolone clearance values were 3.22 +/- 0.88 and 3.46 +/- 0.96 L/h/kg in males and females, respectively. After administration of prednisolone, relative T-cell counts decreased slowly with time to reach a nadir at 3-5 h and returned to baseline levels by 8 h. Fitting data using an indirect response model yielded mean prednisolone 50% inhibitory concentration for inhibition of WBTC trafficking (IC50T) that was lower in males compared with females (0.14 +/- 0.16 versus 1.03 +/- 0.06 ng/mL; p < 0.05). In the absence of RU-40555, an immediate and complete inhibition of 3H-TDR incorporation into WBTC was observed (deactivation) and baseline levels were recovered slowly as prednisolone was cleared from blood. The mean 50% inhibitory concentration for inhibition of WBTC deactivation (IC50D) based on an inhibitory Imax model was similar in males and females (0.20 +/- 0.24 versus 0.18 +/- 0.12 ng/mL). Although male and female rats have similar exposure to prednisolone after 5-mg/kg doses, males are more sensitive to the inhibition of WBTC trafficking, whereas no gender effects on deactivation of WBTC exist.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adrenalectomy
  • Algorithms
  • Animals
  • Area Under Curve
  • Chromatography, High Pressure Liquid
  • Female
  • Hormone Antagonists / pharmacology
  • Lymphocyte Activation / drug effects*
  • Male
  • Mifepristone / analogs & derivatives
  • Mifepristone / pharmacology
  • Models, Biological
  • Prednisolone / pharmacology*
  • Rats
  • Rats, Sprague-Dawley
  • Sex Characteristics
  • T-Lymphocytes / drug effects*
  • Thymidine / metabolism


  • Hormone Antagonists
  • RU 40555
  • Mifepristone
  • Prednisolone
  • Thymidine