PROLIFERATING-CELL NUCLEAR ANTIGEN (PCNA) IN THE HUMAN ADRENAL-GLANDSAT THE END OF THE EMBRYONIC PERIOD

Studies were performed on adrenal glands of 7 human embryos between 6 and 8 weeks of intra-uterine life using clone PC-10 mouse serum (Dako, No. M879). During the 6th week, immunoreactivity for the proliferatin g-cell nuclear antigen (PCNA) was observed only in the central and med ial parts of the developing fetal zone of the adrenal gland (75.2 +/- 3.1% of adrenocortical cells showed nuclei stained with anti-PCNA), wh ile the peripheral part was immunonegative. One week later the second outer layer, i.e. the permanent cortex appeared. During the 8th week, the cortex formed two distinct zones: a relatively large and centrally located fetal zone and a thin rim of definitive (permanent) cortex, t he later adult adrenal cortex. PCNA-positive cells were present throug hout the surface of the gland being most numerous in the center (76.4/-1.4%) and less numerous in the peripheral part (16.6+/-2.6%). A very thin layer of permanent cortex surrounding the fetal zone showed less numerous cells stained for PCNA (36.4+/-3.4%) as compared with the in ner fetal zone. During the 8th week the proliferative cells activity w as similar in both zones. The middle proliferative center of the fetal zone disappeared, and all cells of this zone had similar PCNA reactiv ity.