Transfer of lipids across the guinea pig placenta

Abstract

The extent of transfer of isotope-labeled lipids in both directions across the guinea pig placenta was measured by an in situ perfusion technique. The transfer of albumin-bound C¹⁴–free fatty acids from fetus to mother was from 55 to 63 per cent of the reservoir radioactivity during a single 20minute perfusion. The nature of the fatty acid, whether saturated or unsaturated, of odd- or even-numbered carbon chain length, and whether presented as a single fatty acid or in groups of fatty acids had no measurable effect on transfer rates. The lack of selectivity of transfer of any fatty acid was also seen in the study of maternal to fetal transfer; the placental perfusate level of radioactivity was as much as 35 per cent of the maternal arterial concentration. Transfer of complex lipids measured by this technique was extremely limited. It is noted that the free fatty acids behave like other albumin-bound, organic-soluble compounds in exchanging rapidly across the placenta.