[Effect of different storage times of blood sera on their hormonal activity]

Hormonal activity of the sera was studied immediately after blood collection and 6 months, one year and 1.5 years following their storage at a temperature of -20 to 25 degrees C in 10 healthy males aged 18 to 20 years. It was found that differently directed changes in immunologic activity of blood serum hormones took place on long-term storage at low temperatures. The data obtained suggest that the adrenocorticotropic hormone, immunoreactive insulin, protein-bound iodine and follicle-stimulating hormone retain the immunologic activity not more than one year, while the hormone, stimulating interstitial cells, thyrotrophic hormone, somatotrophic hormone, 17-HOCS, testosterone and aldosterone up to 1-1.5 years. During this storage of frozen biosubstrates the recurrent freezing out that produces changes in the immunologic activity of some hormones should be excluded.