TY - JOUR
T1 - Secretion of a gonadotrophin-releasing hormone- (GnRH-)like factor by the rabbit fetal placenta in vitro
AU - Nowak, Romana A.
AU - Bahr, Janice M.
N1 - Funding Information:
This research was supported by NIH PHS I-RO-I-HD1979-ot and Hatch Funds. We wish to thank Dr Dean Dluzen for help with the GnRH radioimmunoassays and Mr Gregory Erbach for technical assistance with the cannulations. Appreciation is also expressed to Mrs Cathy Ndekwe for her expert clerical assistance and Mr Lynn Warner for care of the animals.
PY - 1987
Y1 - 1987
N2 - Previous studies have shown that the rabbit fetal placenta contains both biological and immunological gonadotrophin-releasing hormone- (GnRH-) like activity. The purposes of this study were to determine whether (1) the fetal placenta secretes a GnRH-like factor, and (2) this GnRH-like factor is secreted into the uterine vein. In experiment 1, fetal placentae were collected from day-18 pregnant rabbits. The placentae were divided in half, and one-half was used for measurement of GnRH; the other half was cut into small pieces and placed into a perifusion system. Following a 2-h stabilization period, tissue was challenged with two 60 mm K+ injections spaced 90 min apart. Six replicates were run with either liver (n = 4) or spleen (n = 2) as control tissues. Basal levels of GnRH secreted (nmol/g protein/30 min) were 1.2 ± 0.3 for placental tissue, 0.3 ± 0.1 for liver tissue and non-detectable for spleen tissue. Following the first K+ injection there was no response from liver or spleen tissue, while placental tissue showed a 78 per cent increase after 90 min. There was no response to the second injection. The concentration of GnRH in the placenta was 6.8 ± 0.5 nmol/g protein. In experiment 2, plasma samples were obtained from the marginal ear vein of five oestrous does and five day-7 pseudopregnant does, and from the marginal ear vein and uterine vein of six day-18 pregnant does. These samples were assayed for GnRH and found to contain 7.1 ± 1.2, 6.3 ± 2.1, 10.2 ± 2.5 and 9.8 ± 2.2 pmol/l, respectively. These data indicate (1) that the rabbit fetal placenta secretes an immunological GnRH-like factor in vitro, and (2) that this GnRH-like factor is not secreted into the uterine vein.
AB - Previous studies have shown that the rabbit fetal placenta contains both biological and immunological gonadotrophin-releasing hormone- (GnRH-) like activity. The purposes of this study were to determine whether (1) the fetal placenta secretes a GnRH-like factor, and (2) this GnRH-like factor is secreted into the uterine vein. In experiment 1, fetal placentae were collected from day-18 pregnant rabbits. The placentae were divided in half, and one-half was used for measurement of GnRH; the other half was cut into small pieces and placed into a perifusion system. Following a 2-h stabilization period, tissue was challenged with two 60 mm K+ injections spaced 90 min apart. Six replicates were run with either liver (n = 4) or spleen (n = 2) as control tissues. Basal levels of GnRH secreted (nmol/g protein/30 min) were 1.2 ± 0.3 for placental tissue, 0.3 ± 0.1 for liver tissue and non-detectable for spleen tissue. Following the first K+ injection there was no response from liver or spleen tissue, while placental tissue showed a 78 per cent increase after 90 min. There was no response to the second injection. The concentration of GnRH in the placenta was 6.8 ± 0.5 nmol/g protein. In experiment 2, plasma samples were obtained from the marginal ear vein of five oestrous does and five day-7 pseudopregnant does, and from the marginal ear vein and uterine vein of six day-18 pregnant does. These samples were assayed for GnRH and found to contain 7.1 ± 1.2, 6.3 ± 2.1, 10.2 ± 2.5 and 9.8 ± 2.2 pmol/l, respectively. These data indicate (1) that the rabbit fetal placenta secretes an immunological GnRH-like factor in vitro, and (2) that this GnRH-like factor is not secreted into the uterine vein.
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U2 - 10.1016/0143-4004(87)90054-3
DO - 10.1016/0143-4004(87)90054-3
M3 - Article
C2 - 3658924
AN - SCOPUS:0023257767
VL - 8
SP - 299
EP - 304
JO - Placenta
JF - Placenta
SN - 0143-4004
IS - 3
ER -