208 DEHYDROISOANDROSTERONE (D) AND OVINE FETAL ESTROGEN PRODUCTION

Estrogen production by fetal and infantile rat ovaries.

The de novo production of estrone and estradiol by the fetal and infantile rat ovary and its regulation by cAMP, LH and FSH were investigated. Basal estrogen secretion was not demonstrable before d 5 after birth. However, the fetal ovary was responsive to cAMP as early as 14 d old. Estrone was the main estrogen secreted. Steroid aromatase inhibitors inhibited cAMP-stimulated estrone secretion. ...

Ontogeny of estrogen sulfatase activity in ovine fetal hypothalamus, hippocampus, and brain stem.

Ovine parturition is initiated by increases in fetal hypothalamus-pituitary-adrenal (HPA) axis activity, which in turn increase placental estrogen biosynthesis and ultimately increase uterine contractility. In addition to the action in the uterus, estrogens augment fetal ACTH secretion. In late gestation, estrone sulfate is more abundant in fetal plasma than is unconjugated estrone. We studied ...

Estrogen acutely activates prostacyclin synthesis in ovine fetal pulmonary artery endothelium.

Prostacyclin (PGI(2)) is a key mediator of pulmonary vasodilation during perinatal cardiopulmonary transition, at a time when fetal plasma estrogen levels are rising. We have previously shown that estradiol-17beta (E(2)) rapidly stimulates nitric oxide production by ovine fetal pulmonary artery endothelial cells (PAEC), and that this occurs through nongenomic mechanisms which are calcium- and t...

Prostaglandin production at the onset of ovine parturition is regulated by both estrogen-independent and estrogen-dependent pathways.

A current hypothesis of ovine parturition proposes that fetal adrenal cortisol induces placental E2 production, which, in turn, triggers intrauterine PG production. However, recent evidence suggests that cortisol may directly increase PG production in trophoblast-derived tissues. To separate cortisol-dependent and estrogen-dependent PG production in sheep intrauterine tissues, we infused single...

Direct Photon Production in 158 A GeV 208 Pb + 208 Pb Collisions