Abstract
It has been shown by Fevold, et al. 1 , 2 that the gonad stimulating-principles of the anterior lobe of the pituitary gland can be extracted almost quantitatively from powdered glands by means of 50% aqueous pyridine. On account of the difficulty in evaporation of the pyridine extract and the molesting odor, other methods of extracting have been used in the following experiments.
It was found that a solution of 6% normal butyl alcohol, or a 3% solution of amyl alcohol in water would also extract the active principles in a very efficient manner. The extract can very easily be concentrated by vacuum distillation at low temperature (below 40°C) so it offers advantages over aqueous pyridine in this respect.
A comparison of the efficiency of the 2 solvents, 50% aqueous pyridine and 6% aqueous butanol, is given below. The procedure used was that given by Fevold, et al., and was the same in both cases. One hundred grams of the dried acetone extracted pituitary gland from horses were used. The material was extracted each time for 12 hours with 700, 600, 600, 600 cc. of the respective solvent—50% pyridine or 6% butyl alcohol solution.
Each extract was then purified as follows: After evaporation in vacuo at a temperature below 40° to a volume of 500 cc, 4 1/2 volumes of acetone were added. The precipitate thus obtained was emulsified in 1,500 cc. of water and 750 cc. of acetone were added. The insoluble material was re-extracted with 33% acetone for a second time. The combined 33% acetone solution was evaporated in vacuo. The residue was emulsified in 500 cc. water, and 70 cc. of saturated alcoholic benzoic acid were added. The material brought down with the precipitate of benzoic acid was washed with acetone to remove the benzoic acid, then extracted twice with 150 cc. of water; the aqueous extract was mixed with the filtrate from the benzoic acid and precipitated with 4 1/2 volumes of acetone.
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