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Alpha 1-adrenergic agents are potent stimulators of ACTH secretion directly at the pituitary level as observed using anterior pituitary cells in primary culture and by in vivo studies. On the other hand, beta-adrenergic as well as antidopaminergic agents are also potent stimulators of ACTH secretion but at a suprapituitary level, since no effect of these compounds are observed in vitro. CRF administration has been found to lead to rapid and parallel increases in ACTH and alpha-MSH concentrations in rat plasma and the mechanism of action of CRF has been studied in vitro using rat anterior and intermediate lobe of pituitary gland for ACTH and alpha-MSH secretion, respectively. In both cases, CRF stimulates adenylate cyclase activity at ED50 values of 70 and 350 nM for ACTH and alpha-MSH, respectively. CRF stimulates adenylate cyclase activity at least partly through a guanyl nucleotide-dependent mechanism. Using rat pars intermedia cells in culture, we have demonstrated the presence, in addition of a CRF receptor, of a beta 2-adrenergic receptor which stimulates cyclic AMP accumulation and alpha-MSH secretion and of a dopaminergic receptor which inhibits cellular activity. These results have been confirmed in in vivo studies where isoproterenol and thioproperazine (a dopamine antagonist) lead to a rapid increase of alpha-MSH secretion.

In 200 dissections of internal jugular veins, the valves were investigated with regard to their constitution, their macroscopic and their microscopic anatomy. In 88% of the cases, an ostial valve was found. The cusp of each consists of two parts in 77%, of only one part in 16%, and in 7% of three parts. In 12% these valves are not found. The structure, the configuration, the topography of these valves are explained. The stroma of the valve consists of collagen and elastic fibrils. The surface of the luminal and parietal part is covered by endothelial cells with elastic and muscular fibers close to the attachment of the cusp to the vein wall.

The pharmacokinetics of the tricyclic antidepressant amineptine (Survector) and its main metabolite were studied in 12 young healthy adults (6 men, 6 women; mean age 35.8 yr). Plasma samples were taken over 24 h following a single oral dose of 100 mg amineptine chloryhdrate. Plasma levels of both compounds were determined by means of high performance liquid chromatography. Amineptine was rapidly absorbed. Mean peak plasma concentrations of amineptine and its metabolite occurred 1 h and 1.5 h, respectively, after product administration. The mean apparent volume of distribution was large: 2.4 l.kg-1. Elimination was rapid; the mean half-lives of the 2 compounds were short: 0.8 h for amineptine and 2.5 h for the metabolite. The mean apparent plasma clearance of amineptine was high (124.8 l.h-1). When the results were adjusted for body weight and surface area, no significant difference in pharmacokinetic parameters was found between men and women. Given its pharmacokinetic characteristics there is no risk of amineptine accumulation and thus it is a particularly easy drug to manage. A standard dosage of amineptine was defined for use in healthy young adults.