Tissue distribution of radioiodinated human growth hormone in the mouse

The distribution of human growth hormone (HGH) labeled with 125I was studied in mature and immature intact mice. The 125I-HGH appeared to be biochemically homogeneous and possessed both biologic and immunologic activity. Uptake of 125I-HGH in mice occurred initially in the liver, but the highest radioconcentration values occurred in the seminal vesicle (SV) of the male mice at 3.0 hr postinjection. Other tissues and organs in the male mice did not take up the radiolabeled HGH. Radio-uptake in a sexually equivalent organ of the female could not be demonstrated. 125I-HGH levels were higher in the SV of immature than in mature male mice; however, this difference was not significant. The use of anti-HGH antiserum employed as a blocking agent specifically inhibited the uptake of 125I-HGH in the SV of the mouse.