Exercise-induced changes in the percentage of free testosterone and estradiol in trained and untrained women

We have studied the effect of exercise on the percentage of free plasma estradiol 17-beta (E2) and testosterone (T) in 13 untrained (UT) and 8 trained (marathon runners, MR) eumenorrheic women. All women performed a standardized bicycle ergometer (UT) or treadmill (MR) test in the follicular and luteal phases of their menstrual cycles (15-min consecutive work loads of 60%, 70%, and 80% VO2 max to exhaustion). Blood was drawn through an indwelling venous catheter at 15 and 2 min before and immediately after exercise. Free E2 and T was assayed by centrifugal ultrafiltration using undiluted plasma at 37 degrees C (basal samples) and 39 degrees C (exercise samples). Statistical analysis was performed by a two-tailed paired t test. In the UT, the basal percentage of free E2 was measured to be 1.55% +/- 0.24% (mean +/- SD) in the follicular phase and 1.62% +/- 0.32% in the luteal phase (differences NS). In the MR, these values were 1.22% +/- 0.25% and 1.25% +/- 0.12% for the follicular and luteal phases, respectively. The differences between the groups were not significant. Exercise did not provoke significant changes in free E2 in either of the groups. Constrastingly, exercise induced a significant (P less than 0.02) increase in the percentage of free T from 1.56% +/- 0.27% to 2.1% +/- 0.36% and from 1.6% +/- 0.27% to 2.12% +/- 0.33% in the UT in the follicular and luteal phases, respectively. In the MR, the free percentage of T increased from 1.04% +/- 0.39% to 1.6% +/-0.16% (follicular phase) and from 1.24% +/- 0.22% to 1.67% +/- 0.18% (P less than 0.02).

Effect of a 3-month endurance training program on metabolic and multiple hormonal responses to exercise

We have investigated the effect of a 3-month endurance training program (running and cycling) on plasma hormone responses during standardized bicycle ergometer work (15-min consecutive work loads of 60%, 70%, 80%, and eventually 90% VO2 max) in eight previously untrained eumenorrheic women. The subjects were investigated before and after training both in the follicular and luteal phases of the menstrual cycle (between the 7th-10th and 20th-25th days of their menstrual cycle, respectively). Blood was obtained 15 and 2 min before the onset of exercise and at the end of each work load from an indwelling catheter. In each sample, the plasma concentrations of estradiol 17 beta (E2), progesterone (P), testosterone (T), androstenedione (delta 4-A), dehydroepiandrosterone sulfate (DHEA-S), prolactin (PRL), and adrenocorticotropic hormone (ACTH) were assayed in duplicate by RIA; lactate was assayed as well. The hormone concentrations were expressed in absolute as well as in relative values. After training basal DHEA-S and ACTH levels were significantly (P less than 0.05) lower in both phases of the menstrual cycle, whereas basal luteal phase E2 and T levels were significantly (0.05 greater than P greater than 0.01) lower after training. Exercise induced significant increments in the relative values of all hormones in both phases (0.05 greater than P greater than 0.001). After training, T and DHEA-S increased relatively more pronounced (0.05 greater than P greater than 0.02) in the follicular and luteal phase, respectively.

Lack of effect of cimetidine on pharmacodynamics and kinetics of single oral doses of R- and S-acenocoumarol

The kinetics and dynamics of single doses (5 mg p.o.) of the optical isomers of acenocoumarol (R-AC and S-AC) were followed in healthy subjects and the effect on them of cimetidine 800 mg/day was also investigated. The AC enantiomers differed greatly in their pharmacokinetics. The mean residence time (MRT) of R-AC was about 10 times longer than that of S-AC, 15 h vs 1.2 h. There was no difference in the volume of distribution. Depression of blood clotting activity (Thrombotest) was observed only after administration of R-AC. The inactivity of S-AC as a vitamin K antagonist must be ascribed to its short MRT. Cimetidine did not affect the acute oral kinetics of R- and S-AC, nor did it affect the anticlotting activity of R-AC. The urinary excretion pattern of the 6- and 7-hydroxylated AC metabolites was not altered during cimetidine treatment. Although the present studies showed no effect of cimetidine on the pharmacokinetics and dynamics of acenocoumarol, the findings of Serlin et al. suggest that cimetidine should not be administered during acenocoumarol therapy.

Ibuprofen: plasma concentrations in man

The plasma levels of ibuprofen were measured in five healthy subjects who took 600 mg tablets of ibuprofen twice daily, three times daily and four times daily in a crossover study. Peak plasma levels were obtained 1 hour after the first dose in all but one subject (slow absorber), the mean peak value being 51.3 micrograms X ml-1 (range 39.4-63.7 micrograms X ml-1). After the repeated dose regimens of two, three or four times daily of ibuprofen, the peak levels achieved were in a similar range to those seen after the first dose: Twice daily 39.4-66.4 micrograms X ml-1; Three times daily 43.6-63.3 micrograms X ml-1; Four times daily 44.1-58.4 micrograms X ml-1. There was no evidence of accumulation of the drug and no side-effects occurred during the trial.