[Adrenocortical zonation in human growth hormone gene (hGH) transgenic mice]

Adrenocortical zonation was histologically examined in 2 infertile female transgenic (Tg) mice which carried human growth hormone (hGH) gene and had a high circulating level of hGH. The adrenal cortices of Tg mice were characterized by the appearance of hypertrophied zona fasciculata cells with the cytoplasm filled with many lipid droplets even in size, the absence of the distinctive z. reticularis and the persistence of the X zone with nodules in one and without them in the other. The last finding might be explained by the reflection of the strain differences used in Tg mouse construction. It was, however, suggested that the X zone degeneration might not be associated with the adenohypophysis. The changes observed in z. fasciculata cells were interpreted as the effects of ACTH-like function of circulating hGH in addition to the known PRL-like function. The absence of the z. reticularis may be explained by its morphological similarity to z. fasciculata under the effects of the circulating hGH at a high level. In addition to genetic analysis of various inbred strains, Tg mice with ectopic hGH production provide a new methodology in analyzing the mechanism of adrenocortical zone formation.