[Radioimmunological method of determining the growth hormone of rats]

The paper is concerned with working out a system of a homologous radioimmunoassay for determination of the growth hormone of rats. The obtaining of all components of the system was described including a specimen of homogeneous highly purified rat STH and a guinea-pig antiserum to it. Conditions for running the RIA which provided for getting a calibrated curve within the range of effective STH doses of 5-1000 ng/ml were described. A study of the specificity of the STH determination method demonstrated that under such conditions LH (rLH-RP-1, NIADDK) and TTH (rTSH-RP-2, NIADDK) did not show activity and rat prolactin revealed insignificant activity equal to 1.3% of STH activity. Using the above method STH levels were determined in the blood plasma of Wistar rats under the following experimental conditions: in intact animals after L-arginine load and 2 weeks after hypophysectomy. STH levels under these conditions were 42 +/- 2.6, 102 +/- 3.8 and 8.6 +/- +/- 1.2 ng/ml, respectively. The authors presented the results of comparative immunological activity of the obtained STH specimen and the STH specimens of rats, NIADDK.