HORMONAL MODULATION OF APOPTOSIS IN THE RAT ADRENAL-GLAND IN-VITRO ISDEPENDENT ON STRUCTURAL INTEGRITY

The intact rat adrenal gland in short-term (3-h) organ culture may be amenable for the identification of factors involved in regulating adre nal cell apoptosis under defined conditions. In this model, culturing in the absence of trophic support (basal; control) triggered apoptosis in the intact rat adrenal gland; oligonucleosome formation, a measure of apoptosis, was 56.4-fold greater than that of glands snap-frozen a t the start of incubation. Angiotensin II (Ang II) (100 nM) enhanced a poptosis by 67% over control, By contrast, adrenocorticotropin (ACTH) (100 nM) attenuated basal apoptosis by 59% and antagonized the enhance d apoptosis induced by Ang II back to the control level. Quartering of the glands enhanced basal oligonucleosome formation 182.2% greater th an that of intact glands. Interestingly, quartering of the glands abol ished the influences of Ang II and ACTH on apoptotic DNA fragmentation , but did not alter ACTH-induced corticosterone secretion. These data suggest that some level of gross adrenal structural information or com partmentalization, sufficiently disrupted by quartering, is required f or the hormonal modulation of adrenal cell survival.