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Sclareol glycol (SG) is a semisynthetic diterpene of the labdanic group. SG is tetranorlabdaniol bivalent alcohol 13, 14, 15, 16-tetranorlabdan-8 alpha, 12-diol, obtained from the plant Salvia sclarea L., grown in Bulgaria. The effects of SG were studied on the level of 3',5'-AMP in:mono-layer tissue cultures of the anterior hypophysis of the rat; in hypophysial and brain tissue during in vitro incubation; in liver microsomes of the rat during in vitro incubation and in liver perfusate of the rat. It was established that SG induced an increase in accumulation of 3,5'-AMP in the tissues from the anterior hypophyses of mature and newborn rats, in the sections of brain cortex and cerebellum of mature rats. Similar changes were found by the diterpene forskolin, studied comparatively. SG induced a reduction of accumulation of 3',5'-AMP in liver microsomes and diminished the release of 3',5'-AMP in a liver perfusate of the rat. The increased accumulation of 3',5'-AMP due to SG could be explained by postreceptor stimulation of the enzyme adenylate cyclase, binding directly to its catalytic subunit. The reduced accumulation of 3',5'-AMP in liver microsomes and its diminished release in liver perfusate could be explained either by activation of the inhibitory adenylate cyclase in hepatocytes or by desensitisation of 3',5'-AMP-generating system.

The effects of a semisynthetic diterpene sclareol glycol (SG) on the release of adenohypophysial hormones prolactin, somatotrophic hormone (STH) and adrenocorticotrophic hormone (ACTH) were studied in the plasma of the rat. The effects of SG were investigated also parallel with diterpene forskolin (F) on the release of prolactin and STH in tissue cultures of adenohypophysial cells of the rat. The experiments established that SG increased in a low dose, but in higher dose lowered the concentration of plasma prolactin and STH. These effects were found even after 15 minutes after its intraperitoneal administration. SG induced mainly an increase of plasma concentration of ACTH. In tissue cultures of adenohypophysial cells SG caused lowering of prolactin concentration and an increase of STH; under these conditions F caused only an increase in the concentration of these hormones. The results show that SG influences secretion of prolactin, STH and ACTH in various ways in comparison with F. This might be due to th their various chemical structure and to their basic mechanisms of action (mainly by 3',5'-AMP for P; besides 3, 5'-AMP substantial participation of DA-ergic and GABA-ergic mediation for SG).