Somatic cell fusion in the study of glucocorticoid action

Factors affecting adrenocortical hormone function

This paper will briefly outline those elements which must be considered in assessing the effects of any given compound which might impinge on the actions of adrenocortical steroids. Considerations that ought to be taken into account include the following: the delivery to the affected cells of corticosteroids, the uptake of the hormone by the cells, the metabolism of the hormone by the cells, the intracellular actions of the hormone, the possible secondary interactions between cells, and multihormonal actions on the final target cell.

Pattern of peptide synthesis in Drosophila cell lines and their hybrids

Significant changes occurred in the rate of synthesis of several polypeptides in two different Drosophila cell lines following exposure to the steroid hormone, beta-ecdysone. For peptide 7/8, the synthetic rate increased by a factor of 10 in line S3 and by a factor of 1.3 in line MDR. In hormone-sensitive hybrids the rate increased by a factor of 3-4.5. For peptide 10 the synthetic rate decreased by a factor of 8 in line S3 but increased by a factor of 2 in line MDR. In hormone-sensitive hybrids the synthetic rate increased by a factor of 2-3. In hormone-insensitive cell lines no change in the rate of peptide synthesis occurred in the presence of hormone.

Acetylcholinesterase induction by beta-ecdysone in Drosophila cell lines and their hybrids

Drosophila S3 line cells maintain a high basal level of acetylcholinesterase (AChE) activity, which is lost and then reinduced following exposure to the steroid, beta-ecdysone. Electrophoretic studies indicate that the basal and reinduced AChE activities may be different isozymes. In contrast, MDR line cells have a low basal AChE activity which is induced to a modest level by hormone. In S3/MDR hybrids the high basal level phenotype is extinguished, and the hormone-induced AChE level is modest. MDER line cells, which continue to grow in the presence of beta-ecdysone and are therefore termed resistant, show a low basal AChE level that is not further elevated by hormone. This phenotype and response also occurred in beta-ecdysone-resistant S3/MDER hybrids.