THE ACTION OF RADIX REHMANNIAE AND PLASTRUM TESTUDINIS ON BETA- ADRENERGIC RECEPTOR-cAMP SYSTEM

Mouse and rat pathological models were pro duced by injections of thyroid hormone (T3 0r T4, Model. I) or hydrocortisone (HC, Model II). A single subcutaneous dose of isoproterenol (ISO) caused plasma cAMP to peak in 5-15 min which was significantly higher in mouse Models I and II than in normal mice. Daily oral administration of a decoction of two Yin tonics-Radix Rehmanniae (RR) and Plastrum Testudinis (PT) reduced peak cAMP in both models. 3H.DHA binding assay re vealed significant elevations of the number of 3 adrenergic receptors in rat Models I and II. Decoc- tion RR and PT restored the peaks to normal range. Yang tonics Radix Aconiti praeparata (RAP) and Cortex Cinnamomi (CC) showcd contradictory effects on these models. It seems unlikely that the action of the two tonics promotes the dlearance of injected hormones, since injected hormone RIA iii plasma showed no differences between Yin tonics treated and untreated models. The therapeutic effects of these two Yin tonics on "Yin deficiency" syndrome of hyperthyroidism or hyperfunction of the adrenal cortex is very probably related to their actions on the O-adrenoreceptor-cAMP system as stated.