Placental perfusion. An overview of the literature.
Placental perfusion techniques are currently used to study not only the organ functions but also the transfer profile and metabolic pathway of different compounds. In view of the interest in the mechanism of transfer and potential adverse effects of compounds there are numerous publications on the topic, but no systematic picture is yet available. Thus an overview has been made of all studies published from 1966 to 1990 that use this experimental approach. Out of 359 computer-retrieved articles, 266 (74%) actually dealt with the target topic; 68 articles were added after a systematic hand search, so a total of 334 articles were analyzed. The distribution of papers per year was constant until 1980, and rose significantly thereafter. Animal studies using placental perfusion were performed either in situ or in vitro, whereas human investigations were mostly examined by in vitro perfusion techniques. Animal experiments were done on seven species, the guinea pig being the most widely used. The aims of all studies could be divided into five main categories: 132 studies researched the kinetics of compounds in the placenta; 100 studies investigated placental metabolism; methodology of perfusion was reported in 22 articles; and 49 studies examined physiological changes of placental variables. A clear increase in pharmacological studies was noted starting from 1986 (there were 31 such studies). Compounds studied were either endogenous or exogenous. Almost all endogenous compounds were investigated, some of them quite extensively (mainly hormones, angiotensin, glucose, and lactate). There seemed to be no preferential field for exogenous compounds (62 compounds could be assigned to 20 classes).(ABSTRACT TRUNCATED AT 250 WORDS)