Enzymic differentiation of rat yolk-sac placenta as affected by a teratogenic agent

During the very critical stages of early differentiation and organogenesis in the rat, the yolk-sac epithelium would appear to be the only available site for major transport, even during somewhat later embryonic stages.

Abstract

ABSTRACT Electrophoretic and biochemical techniques were applied to homogenates of the rat’s visceral yolk-sac. Non-specific esterase, acid phosphatase, malate and lactate dehydrogenases were shown, by electrophoretic techniques, to undergo sequential enzymic differentiation from day 10 through day 20 of gestation. The enzyme repertory on a particular day was achieved through both additions to and deletions from the repertory of the preceding day. The greatest staining intensity by esterase and acid phosphatase was late in gestation but for both malate and lactate dehydro-genase it was most intense during days 11–13. A teratogenic folic acid deficiency resulted in delayed appearance of several enzyme forms but also resulted in some forms persisting beyond their normal time for disappearance. The effects of the vitamin deficiency were quite selective in that some enzyme forms appeared on time and in apparently normal concentration in the PGA-deficient material.