Worcester Foundation for Biomedical Research

About: Worcester Foundation for Biomedical Research is a based out in . It is known for research contribution in the topics: Estrone & Estrogen. The organization has 2195 authors who have published 2646 publications receiving 115809 citations. The organization is also known as: Worcester Foundation for Experimental Biology.

Estimation of Androstenedione in Human Peripheral Blood with 35S-thiosemicarbazide

Abstract: A double isotope derivative technique using 35S-thiosemicarbazide and 3H indicator for estimation of androstenedione in 10 ml peripheral plasma is described. Radiochemical isolation is achieved with 2 thin layer and 2 paper chromatographic steps utilizing pyruvic acid hydrolysis for further derivative formation. With this method, plasma from ovariectomized-adrenalectomized subjects or 10 ml water blanks give values of 0.015 ±0.006 (sd) μg/100 ml. Male plasma contains 0.075 ±0.004 (se) and female plasma contains 0.145 ±0.017 (se) in the follicular phase and 0.160 ±0.010 (se) μg/100 ml in the luteal phase of the cycle (values not corrected for mean blank). Accuracy and precision studies do not indicate the presence of a systematic error. A comparison of plasma levels of both androstenedione and testosterone suggests that minimal blood testosterone is converted to blood androstenedione, but the excess concentration of androstenedione in the female could indicate that this steroid may be a major peripheral pr...

Ethanol effects on voltage-dependent membrane conductances: comparative sensitivity of channel populations in Aplysia neurons

Abstract: 1. The study of ethanol (EtOH) action is interesting because of its clinical relevance and for the insights it provides into structure-function relationships of excitable membranes. This paper describes the concentration dependencies of various parameters of four currents inAplysia cells. 2. ICa is the most sensitive of the currents studied. There was a significant reduction ofICa at concentrations of 50 mM EtOH. At low concentrations, the reduction of amplitude was the primary effect of ethanol, with the kinetics and voltage dependency of activation not affected. 3. INa andIA were also affected, but at EtOH levels higher than those which alteredICa. The primary effect of EtOH onINa was a reduction in its amplitude, although the time to peak current flow was increased by EtOH. The effects of EtOH onIA were cell specific and, for the purposes of this paper, we examined the giant metacerebral cell (MCC). In MCC, the primary effect of EtOH onIA was an increase in the time course of inactivation. The time to peakIA was also increased by high concentrations of EtOH, but its amplitude was unaffected even at high concentrations. The delayed rectifier current,IK, was the most EtOH resistant of the currents examined. High EtOH concentrations augmented the amplitude ofIK, although even at 600 mM concentrations, the percentage change was only 30%. 4. Our results indicate that the calcium channel is very susceptible to the influence of ethanol and is a serious candidate to be the primary target of EtOH action in the nervous system. 5. The differential sensitivity of voltage-dependent currents and individual components of a given current suggests further experiments to probe the relationship between membrane structure and channel function in excitable membranes.