GENETIC DIFFERENCES IN THE CORTISOL CONCENTRATION OF THE ADRENAL AND OTHER TISSUES OF WHITE AND COLOURED GUINEA-PIGS

Abstract

SUMMARY The effect of genetic difference (white v. coloured) on the cortisol content of ten different organs and tissues, including the adrenals, of white and coloured guinea-pigs of both sexes and of different ages was studied by protein-binding techniques. Tissue cortisol concentration was significantly higher in all the tissues and adrenals of white animals of both sexes compared with coloured animals. The difference in tissue cortisol content between white and coloured animals was higher before (range 41·5–134·%) than after puberty (range 10·1–82·5%). The age-dependent decrease of cortisol concentration in different tissues and adrenals in adults was more marked in white guinea-pigs of both sexes (mean 30·6%, range 0·0–71·5%) than in coloured (mean 16·9%, range 0·0–63·1%). In adult animals the liver contained significantly 11·8–36·4%) more cortisol than in prepubertal animals. This pattern was the same in white and coloured guinea-pigs of both sexes.