Steroid-protein interaction in human placenta.
Human placenta produces a large variety of bioactive substances with endocrine and neural competence: pituitary and gonadal hormones, hypothalamic-like releasing or inhibiting hormones, growth factors, cytokines and neuropeptides. The most recent findings indicate that locally produced hormones regulate the secretion of other placental hormones supporting a paracrine/autocrine regulation. In placental endocrinology, a particular relevance is played by steroid hormones. In fact, a specific gonadotropin-releasing hormone (GnRH)-human chorionic gonadotropin (hCG) regulation of placental steroidogenesis has been proposed as a placental internal regulatory system acting on steroids production from human placenta. In addition, activin and inhibin have been proposed as further regulatory substances of the synthesis and secretion of steroids; the addition of activin A to placental culture augments GnRH, hCG and progesterone, and this effect can be significantly reduced by the addition of inhibins. Finally, a steroid-steroid interaction is suggested by the evidence that placental estrogen has a positive role in the regulation of progesterone biosynthesis. Other steroid-protein interactions have been observed in human placenta. In fact, recent data indicate that progesterone inhibits placental corticotropin-releasing factor (CRF) and estrogens act on placental conversion of cortisol to cortisone, activating cortisol secretion by the fetal adrenal and enhancing fetal adrenal function with advancing gestation.
Petraglia
F
F
Department of Gynecological, Obstetric and Pediatric Sciences, University of Modena, School of Medicine, Italy.
de Micheroux
A A
AA
Florio
P
P
Salvatori
M
M
Gallinelli
A
A
Cela
V
V
Palumbo
M A
MA
Genazzani
A R
AR
D000818:Animals; D003346:Corticotropin-Releasing Hormone / Q000502:physiology*; D004967:Estrogens / Q000502:physiology*; D005938:Glucocorticoids / Q000502:physiology*; D006801:Humans; D010920:Placenta / Q000502:physiology*; D011374:Progesterone / Q000502:physiology*
D004967:Estrogens; D005938:Glucocorticoids; D011374:Progesterone; D003346:Corticotropin-Releasing Hormone