Effect of constant light on fetal and maternal prolactin rhythms in sheep.

摘要: A 24-h rhythm of plasma PRL is present in fetal sheep. This synchronized to an environmental clue (zeitgeber). We determined whether the light-dark cycle (L:D) a zeitgeber for and, if so, mother might convey this fetus. kept nine ewes (twin pregnancies) constant light (L:L) and five (singleton) 14:10 L:D from 110 days gestation. Fetuses mothers were catheterized at 119 Blood samples taken hourly 24 h after 16 under L:L or L:D. mean was found (by RIA) fetuses L:D, but not those L:L. However, showed individual rhythms (cosinor analysis) whose acrophases distributed around clock. Nonsynchronized persisted 23 30 Acrophases within set twins closer than between sets, suggesting that responding common signal. These findings indicate i...