PROGESTERONE CONCENTRATIONS AND CONTENTS IN THE PLASMA, OVARY, ADRENAL-GLAND AND PLACENTA OF THE PREGNANT NATAL CLINGING BAT MINIOPTERUS-SCHREIBERSII NATALENSIS

Reproduction in the Natal clinging bat in South Africa at 25 degrees S is characterized by fertilization in April, implantation during July and parturition in November. In the present study plasma progesterone concentrations peaked two months before implantation, this coinciding with significant peaks in ovarian progesterone content and concentrati on. Plasma progesterone concentrations remained relatively low during and after implantation, but increased significantly during the limb bu d stage to peak levels one month before parturition. Adrenal progester one content and concentration did not follow a specific trend; post-im plantation ovarian progesterone content and concentration remained at baseline values. Placental progesterone content increased significantl y with foetal weight (age). The present study showed that pregnancy in these bats is characterized by two major sources of progesterone, wit h the ovary as the primary source before implantation and the placenta the primary source during embryonic and foetal development.