Effect of fasting on aggregation of hepatocyte rough endoplasmic reticulum in adrenalectomized and 3'MeDAB-treated rats: quantitative electron microscope study.

Abstract

A method for the quantitative analysis of the degree to which hepatocyte rough endoplasmic reticulum (ER) is arranged into parallel arrays was used to study the effect of fasting on rough ER aggregation in rat liver cells following either bilateral adrenalectomy or administration of the carcinogenic azo dye 3'-methyl-4-dimethylaminoazobenzene (3'MeDAB). One group of male inbred Leeds strain rats was subjected to bilateral adrenalectomy (ADX): after 1 week half of the animals were fasted for 24 h whereupon the whole group was killed. A second group of rats, fed for 4 weeks on a diet containing 0.06% of the carcinogenic azo dye 3'MeDAB, was similarly divided into two groups that were killed either with or without a prior 24-h fast. Untreated control groups of rats, both fasted and unfasted, were also killed. A quantitative electron microscope study was carried out to investigate the effect of each treatment on the degree to which the hepatocyte rough ER was aggregated into parallel arrays. ADX alone was without effect but caused a dramatic fall in rough ER aggregation when combined with fasting. At least as great an effect was induced by 3'MeDAB, with or without fasting, while fasting alone had a significant but much more modest effect than either ADX or the carcinogen. Thus, two disparate treatments induced morphologically identical responses in hepatocyte rough ER. The implications of this are discussed in terms of known interrelations between glucocorticoids and chemical carcinogenesis in the rat liver.