An electron microscopic study of the adrenal cortical tissue of the domestic fowl

Summary The fine structure of the adrenal cortex of the domestic fowl has been studied from the 14th day of embryonic life to 980 days after hatching, using the electron microscope.Many mitochondria and vacuoles, round or oval, are observed in all cortical cells. The cristae mitochondriales are not laminar but villous. In the embryo, the mitochondria, whose cristae are not as well developed as those in chick and hen, are very low in electron density. Cytoplasmic vacuoles, either rough or smooth-surfaced, and with a homogeneous content of low electron density, are enclosed by a similar limiting membrane. Some of them are formed by the outer nuclear membrane and are characterized by many small particles on their outer surfaces. These vacuolated structures are perhaps parts of the endoplasmic reticulum. In the 980 day old hen, a number of osmiophilic droplets, round or irregularly shaped, are seen. Some of these are formed by mitochondria, while others accumulate within or around cytoplasmic vacuoles. In the embryo and in the chick, such droplets are never seen. It is assumed that the droplets are substances related to ageing, and that the lipid implicated in cortical hormone is not osmiophilic in the young chick and the embryo. It is perhaps produced in the cytoplasmic vacuoles with the aid of mitochondria. A perisinusoidal space and interparenchymatous cell spaces similar to those described for mammals by other workers, are observed in the adrenal gland of the domestic fowl. I assume that the secretory substance of the cortical and the medullary cell is first secreted into these spaces and then infiltrates into the capillary lumen.