Hepatic messenger ribonucleic acid activity profile of rats subjected to alterations in thyroidal and adrenocortical states: evidence for significant interaction.

We have previously established the value of 2-dimensional electrophoretic mRNA activity profiles for investigating the hepatic genomic response to several metabolic perturbations, such as thyroid hormone or GH treatment, diabetes, high carbohydrate diet, starvation, and uremia. We now report the effects of adrenalectomy and dexamethasone treatment, and compare these with alterations due to thyroidectomy and T3 treatment. Total rat hepatic RNA was isolated and translated in a reticulocyte lysate system. The [35S]methionine-labeled translated products were separated by 2-dimensional gel electrophoresis and quantified with computerized videodensitometry. Of 200 consistently quantifiable products, 14 (7%) were altered by adrenalectomy and dexamethasone, including 4 products (46, 47, 56, and 57) which have not been observed to change in previous studies from this laboratory. Adrenalectomy increased 5 and decreased 2 products, whereas dexamethasone increased 1 and decreased 8 products. Two products maintained the same directional shift in the transitions form adrenalectomy to control and from control to the dexamethasone-treated state. Thyroidectomy and T3 altered 13 products. Thyroidectomy increased 2 and decreased 7 products, whereas T3 treatment increased 6 and decreased 3 products. Four products maintained the same directional shift in the transitions from thyroidectomy to control and from control to the T3-treated state. In all of the manipulations performed (adrenalectomy, thyroidectomy, dexamethasone treatment, and T3 treatment), a total of 20 separate products changed. One third were affected by alterations of both the steroidal and thyroidal states. However, when adrenalectomy and thyroidectomy were compared, only 7% of the shifts were concordant, whereas 30% of the shifts were concordant when treatment with dexamethasone and T3 were compared. These results demonstrate that the mRNA activity response is highly specific for each hormonal manipulation. In addition, unanticipated interrelationships between steroidal and thyroidal states were observed. In some, the presence of T3 appears necessary for the suppressive effect of dexamethasone. Others show that T3 appears to inhibit a stimulatory effect of dexamethasone. Specificity of response to dexamethasone is emphasized by the lack of response to vitamin D, deoxycorticosterone, and dihydrotestosterone and by a different response to estradiol from dexamethasone.