BIOASSAY OF STEROID HORMONES USING AQUEOUS SODIUM LAURYL SULFATE SOLUTION AS THE DISPERSING AGENT

Abstract

Na lauryl sulfate with estradiol or testosterone formed an aqueous colloidal soln. which was used on parenteral admn. to delay resorption effectively. An assay procedure for estradiol in biologic systems, using Na lauryl sulfate in aqueous soln. as the dispersing agent was described. With 8-10 rats/ dosage level, the accuracy of the assay was within 15%, 19 of 20 times. The method controlled the influence of certain inert substances which if present might produce augmentation by delaying resorption. The sensitivity (increase in wt./ [gamma]) and maximum degree of uterine wt. stimulation produced by estradiol in the immature rat were markedly effected by delayed resorption. In the expts. recorded, a difference of 400% was observed. The maximum effective response to estradiol was produced solely by a uniform liberation of the hormone. An excess of hormone did not produce antagonism. The dosage level response curve for estradiol, while approaching that produced by chorionic gonadotrophin as the uniform liberation of steriod hormone was more perfectly attained, never reached the efficiency of the response to gonadotrophin. The response to testosterone both for seminal vesicles and uterus was more effective when the vehicle was aqueous sodium lauryl sulfate soln. than when the hormone was dissolved in sesame oil.