TY - JOUR
T1 - Administration of prostaglandin F2(α) during the early bovine luteal phase does not alter the expression of ET-1 and of its type a receptor
T2 - A possible cause for corpus luteum refractoriness
AU - Levy, N.
AU - Kobayashi, S.
AU - Roth, Z.
AU - Wolfenson, D.
AU - Miyamoto, A.
AU - Meidan, R.
PY - 2000
Y1 - 2000
N2 - Luteal regression is initiated by prostaglandin F2(α) (PGF2(α)). In domestic species and primates, demise of the corpus luteum (CL) enables development of a new preovulatory follicle. However, during early stages of the cycle, which are characterized by massive neovascularization, the CL is refractory to PGF2(α). Our previous studies showed that endothelin-1 (ET-1), which is produced by the endothelial cells lining these blood vessels, plays a crucial role during PGF2(α)-induced luteolysis. Therefore, in this study, we compared the effects of PGF2(α) administered at the early and mid luteal phases on ET-1 and its type A receptors (ETA-R) along with plasma ET-1 and progesterone concentrations, and the mRNA levels of PGF2(α) receptors (PGF2(α)-R) and steroidogenic genes. As expected, ET-1 and ETA-R mRNA levels were markedly induced in midcycle CL exposed to luteolytic dose of PGF2(α) analogue (Cloprostenol). In contrast, neither ET-1 mRNA nor its receptors were elevated when the same dose of PGF2(α) analogue was administered on Day 4 of the cycle. In accordance with ET-1 expression within the CL, plasma ET-1 concentrations were significantly elevated 24 h after PGF2(α) injection only on Day 10 of the cycle. The steroidogenic capacity of the CL (plasma progesterone as well as the mRNA levels of steroidogenic acute regulatory protein and cytochrome P450(scc)) was only affected when PGF2(α) was administered during midcycle. Nevertheless, PGF2(α) elicited certain responses in the early CL: progesterone and oxytocin secretion were elevated, and PGF2(α)-R was transiently affected. Such effects probably result from PGF2(α) acting on luteal steroidogenic cells. These findings may suggest, however, that the cell type mediating the luteolytic actions of PGF2(α), possibly the endothelium, could yet be nonresponsive during the early luteal phase.
AB - Luteal regression is initiated by prostaglandin F2(α) (PGF2(α)). In domestic species and primates, demise of the corpus luteum (CL) enables development of a new preovulatory follicle. However, during early stages of the cycle, which are characterized by massive neovascularization, the CL is refractory to PGF2(α). Our previous studies showed that endothelin-1 (ET-1), which is produced by the endothelial cells lining these blood vessels, plays a crucial role during PGF2(α)-induced luteolysis. Therefore, in this study, we compared the effects of PGF2(α) administered at the early and mid luteal phases on ET-1 and its type A receptors (ETA-R) along with plasma ET-1 and progesterone concentrations, and the mRNA levels of PGF2(α) receptors (PGF2(α)-R) and steroidogenic genes. As expected, ET-1 and ETA-R mRNA levels were markedly induced in midcycle CL exposed to luteolytic dose of PGF2(α) analogue (Cloprostenol). In contrast, neither ET-1 mRNA nor its receptors were elevated when the same dose of PGF2(α) analogue was administered on Day 4 of the cycle. In accordance with ET-1 expression within the CL, plasma ET-1 concentrations were significantly elevated 24 h after PGF2(α) injection only on Day 10 of the cycle. The steroidogenic capacity of the CL (plasma progesterone as well as the mRNA levels of steroidogenic acute regulatory protein and cytochrome P450(scc)) was only affected when PGF2(α) was administered during midcycle. Nevertheless, PGF2(α) elicited certain responses in the early CL: progesterone and oxytocin secretion were elevated, and PGF2(α)-R was transiently affected. Such effects probably result from PGF2(α) acting on luteal steroidogenic cells. These findings may suggest, however, that the cell type mediating the luteolytic actions of PGF2(α), possibly the endothelium, could yet be nonresponsive during the early luteal phase.
KW - Corpus luteum
KW - Corpus luteum function
KW - Gene regulation
UR - http://www.scopus.com/inward/record.url?scp=0033882797&partnerID=8YFLogxK
U2 - 10.1095/biolreprod63.2.377
DO - 10.1095/biolreprod63.2.377
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C2 - 10906040
AN - SCOPUS:0033882797
SN - 0006-3363
VL - 63
SP - 377
EP - 382
JO - Biology of Reproduction
JF - Biology of Reproduction
IS - 2
ER -