Transplacental transfer of a growth hormone-releasing hormone peptide from mother to fetus in the rat.
Previous studies showed that when growth hormone-releasing hormone (GHRH) was administered to either pregnant rats or pigs as a plasmid-mediated therapy, pituitary weight, somatotroph and lactotroph numbers, and postnatal growth rate of the offspring increased. To determine if these responses resulted from direct effects of GHRH on the fetus or were secondary to effects incurred in the mother, we studied in the rat the transplacental transfer of a GHRH analog (HV-GHRH) to the fetus from the maternal circulation. For the in vivo study, HV-GHRH was labeled with 125I and purified by reverse-phase high-performance liquid chromatography (HPLC). At 18 days of gestation, pregnant dams were administered a priming intravenous dose followed by a constant infusion of the labeled peptide. Approximately 2 days later, intact [125I]-HV-GHRH was isolated from the fetal liver, stomach contents, and brain. The amounts of tracer were positively correlated with those present in the corresponding dam's plasma. These data suggest that a GHRH analog of nonplacental origin, even at physiologic concentrations, can cross the placenta and, therefore, has the potential to influence fetal pituitary development directly.
Fiorotto
Marta L
ML
USDA/ARS Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas 77030, USA. martaf@bcm.edu
Lopez
Rusmely
R
Oliver
William T
WT
Khan
Amir S
AS
Draghia-Akli
Ruxandra
R
D000818:Animals; D002851:Chromatography, High Pressure Liquid; D005260:Female; D005333:Fetus / Q000378:metabolism*; D006868:Hydrolysis; D008431:Maternal-Fetal Exchange; D009842:Oligopeptides / Q000378:metabolism*; D011247:Pregnancy; D051381:Rats
D009842:Oligopeptides; C420120:gamma-aminobutyryl-2-methyltryptophyl-2-methyltryptophyl-2-methyltryptophyl-lysinamide