Autoradiographic Demonstration of Glomerular Filtration and Proximal Tubular Absorption of Growth Hormone ¹²⁵l in the Mouse

Abstract

Human growth hormone (HGH) labelled with ¹²⁵I was injected intravenously in male mice and the animals were decapitated at intervals ranging from 15 seconds to 30 minutes thereafter. Autoradiographs were prepared from histological sections of the kidneys and showed radioactivity in the glomeruli, Bowman's capsule, proximal tubular lumina and, in concentration, in proximal tubular cells. Maximal radioactivity was found 15 seconds after HGH administration in the glomeruli and after 5 minutes in the proximal tubular cells, localisation being most evident in the luminal half.

These observations suggest that HGH is filtered at the glomerulus and absorbed in the proximal tubules.

Key words

Human Growth Hormone ¹²⁵I - Autoradiography - Glomerular Filtration and Tubular Absorption

1 Present address: Department of Medicine, University of Witwatersrand, Hillbrow, Johannesburg, South Africa.

2 Radiochemical Centre, Amersham.