The hypothesis that receptors in the heart or pulmonary vasculature initiate a reflex that influences urine flow was derived from experiments designed to evaluate the effect of mechanical ventilation on renal function...
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The hypothesis that receptors in the heart or pulmonary vasculature initiate a reflex that influences urine flow was derived from experiments designed to evaluate the effect of mechanical ventilation on renal function. These experiments indicated that urine flow usually decreases during positive-pressure breathing and usually increases during negative-pressure breathing. It was surmised that impulses from certain cardiopulmonary receptors affect the secretion of ADH, which in turn influences urine flow. A subsequent investigation appeared to localize the pertinent receptors to the left atrium, but the results of this particular investigation were influenced by several complication factors that have not been widely appreciated. The apparent localization of volume-regulating recpetors to the left atrium and the accumulating evidence that atrial receptors do respond to changes in atrial pressure or atrial volume triggered a myriad of further studies on the function of left receptors. Nearly all these studies employed indirect techniques that produced changes in systemic and pulmonary hemodynamics in addition to changes in left atrial pressure. Nevertheless, it often was assumed that if changes in left pressure were produced, any concomitant changes in circulating ADH or in urine flow were attributable to a reflex elicited from atrial receptors. Mush of the data obtained were interpreted as being compatible with the elft atrial volume-receptor hypothesis, but very liggle of the data pertained to left atrial receptors specifically.
The two genes coding for thyroid hormone receptors (TR) alpha 1 and beta have opposite effects on female sex behaviors. Deletion of TR alpha 1 reduced them, whereas deletion of TRP actually increased them. These resul...
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The two genes coding for thyroid hormone receptors (TR) alpha 1 and beta have opposite effects on female sex behaviors. Deletion of TR alpha 1 reduced them, whereas deletion of TRP actually increased them. These results could not be attributed to altered levers of hormones in the blood, general alterations in estrogen responsiveness or altered general activity. Instead, they indicate a previously unknown molecular mechanism upon which the two TR genes exert opposite influences.
A fluorometric method for the quantitative assay of vasopressin and oxytocin in individual rat pituitaries has been developed. Acid extracts of pituitaries are freed of amino acids and polyamines by passage over a cop...
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A fluorometric method for the quantitative assay of vasopressin and oxytocin in individual rat pituitaries has been developed. Acid extracts of pituitaries are freed of amino acids and polyamines by passage over a copper-Sephadex column, and the peptides fraction is then labeled by reaction with fluorescamine. The resulting peptide fluorophors are separated by chromatography on a reverse-phase bonded column. Specificity of the procedure was ascertained by several criteria, including bioassay and amino-acid analysis of the eluted peptide fluorophors. The procedure serves as a model system for the assay of tissue peptides in the picomole range.
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