97/00079 Improved techniques for dewatering of fine clean coal

Abstract

The kinetics of disappearance of endogenous mouse placental lactogen-II (mPL-II) were determined in day 12 and day 16 pregnant Swiss Webster mice and in day 16 pregnant mice that had been hypophysectomized (hypox) on day 12. Blood samples from anesthetized animais were taken at différent time intervais after bilateral hysterectomy and the maternai serum mPL-II concentration was measured by homologous radioimmunoassay (RIA). Disappearance curves of mPL-II for day 12 and day 16 pregnant mice were resolved into two exponential components: a rapid phase of disappearance, followed by a slow phase. Although the serum mPL-II concentration was higher on day 16 of pregnancy than on day 12, the a rate constant for the fast component of the disappearance curve for day 12 pregnant mice (0.054 ± 0.005 ml/s) was similar to the value observed for day 16 animais (0.052 ± 0.005 ml/s). The half-life of the fast component of the disappearance curve for day 12 and day 16 pregnant mice was 13.3 ± 0.9 s and 14.8 ± 1.5 s, respectively. The slow component of the disappearance curves for day 12 and day 16 pregnant mice had a β rate constant of 0.00088 β 0.00017 ml/s and 0.00083 ± 0.00009 ml/s, respectively. The half-life of the slow phase of the disappearance curves for day 12 pregnant mice was 1216.4 ± 376.0 s, while the slow phase of day 16 disappearance curves displayed a half-life of 954.4 ± 102.7 s. The similar kinetics of disappearance of mPL-II on days 12 and 16 of gestation suggest that the higher serum mPL-II concentration on day 16 of pregnancy relative to day 12 is not due to a decrease in the clearance rate of the hormone. Hypophysectomy resulted in a dramatic change in the disappearance curve of endogenous mPL-II. The disappearance curve for sham controls consisted of two exponential components, whereas the disappearance curve of mPL-II in hypox animais displayed a single exponential component. The a rate constant was significantly lower in hypox mice (0.0032 ± 0.0003 ml/s) than in sham controls (0.031 ± 0.006 ml/s). Consequently, a 10-fold increase in the initial phase half-life of mPL-II was observed in hypox animais as compared to sham controls (226.3 ± 25.1 s vs. 23.8 ± 4.1 s). The significant decrease in the initial rate constant as well as the increase in the half-life of mPL-II after hypophysectomy suggest that the pituitary gland is involved in regulating the kinetics of disappearance of this hormone.