| Abstract: | Sensitivity of the adenylate cyclase signaling system (ACSS) to polypeptide hormones and biogenic amines is studied in testis and ovary of rats after the 2- and 4-day fasting as compared with control animals. In tissues of the fasted rats there is shown a decrease in the basal activity of adenylate cyclase (AC) and of the basal level of the GTP binding of heterotrimeric G protein. An increase of duration of fasting from 2 to 4 days led to intensification of these changes. In the fasted rats, the stimulating effects of chorionic gonadotropin, PACAP-38. and isoproterenol on the AC activity realized via G protein of the stimulatory type are enhanced, whereas the inhibitory effects of somatostatin on the AC activity realized via G protein of the inhibitory type are reduced. In testis of the fasted rats the stimulating effect of serotonin acting on AC via both types of G proteins are increased, while the inhibitory effects of the hormone decrease. Thus, under conditions of fasting, in rat testis and ovary the ACSS sensitivity to regulatory effects of hormones is changing: its stimulatory effects are increased, while its inhibitory effects, on the contrary, are decreased. We suggest these changes is one of the key mechanisms of adaptation of organism to deficiency of nutritional resources to be aimed at intensifying the tissues catabolic processes, preferably, lypolysis. |
