SYMPATHETIC EFFECTS ON THE STEROIDOGENESIS AND PROLIFERATION OF ADRENOCORTICAL-CELLS IN-VITRO

Recent evidence supports the hypothesis that sympathetic neurons play a significant role in the regulation of adrenocortical cell proliferat ion and steroidogenesis. Co-cultures of rat adrenocortical and sympath etic ganglion cells have been established to study sympatho-adrenal in teractions. In these studies we have compared differentiation, growth and secretion of adrenocortical cells grown in co-culture with those g rown alone. Adrenocortical cells were identified using 3 beta-hydroxys teroid dehydrogenase (3 beta HSD) histochemistry or immunocytochemistr y; sympathetic neurons were identified using immunocytochemical locali zation of tyrosine hydroxylase. The sympathetic neurons usually form c lusters of 3-10 cells, and extend neurites to adrenocortical cells. Ad renocortical cells continue to proliferate, express 3 beta HSD and seq uester lipid droplets. In the co-cultures, the adrenocortical cells ar e smaller, form larger clusters and show denser 3 beta HSD staining th an the adrenocortical cells alone. The presence of the sympathetic neu rons enhances adrenocortical cell proliferation as shown by a 2 fold i ncrease in the number of 3 beta HSD(+) cells as well as increased BrdU incorporation after 48 hrs. Steroidogenesis appeared to be enhanced i n the presence of sympathetic neurons as demonstrated by 3 beta HSD(+) staining and a 2 fold greater corticosterone and aldosterone secretio n. However, when secretion is expressed per number of adrenocortical c ells, the rates are comparable, indicating that secretion rate per cel l remains unaltered by the presence of neurons. The effects of sympath etic neuron activation on adrenocortical cells remain to be determined .