Fetal development, and placental and maternal plasma concentrations of progesterone in the little brown bat (Myotis lucifugus).
Progesterone concentrations measured in plasma samples from 280 bats captured during pregnancy or early lactation were related to fetal attributes indicative of stage of pregnancy. Fetal weight increased exponentially from 40 mg at crown-rump length of 6 mm to 2000 mg at 23 mm (term). Fetal weights at term accounted for up to 35% of the weight of intact pregnant animals. Progesterone concentrations increased from less than 5 ng/ml at 2 mm estimated crown-rump length to plateau values of approximately 65 ng/ml (geometric means) from 16 mm crown-rump length until the most advanced stages of pregnancy. Mean concentration in 8 post-partum bats, most of which were actively lactating, was 8.4 ng/ml; 11.6 ng/ml was measured in one animal that was carrying a wet neonate when sampled yet was still pregnant when captured 5 h earlier. Placental concentrations of progesterone ranged from 43 to 964 ng/g wet weight of tissue and mean values increased in a similar fashion though were about 4-fold greater than changes in plasma concentrations of the steroid. The concentrations in placental tissue were at least 15- to 20-fold higher than could be expected from blood contamination, indicating that placental steroidogenesis is likely to occur in this species.
Currie
W B
WB
Department of Animal Science, Cornell University, Ithaca, NY 14853-4801.
Blake
M
M
Wimsatt
W A
WA
D000818:Animals; D002685:Chiroptera / Q000502:physiology*; D005314:Embryonic and Fetal Development; D005260:Female; D010920:Placenta / Q000032:analysis*; D011247:Pregnancy; D011374:Progesterone / Q000032:analysis* / Q000097:blood
D011374:Progesterone