TY - JOUR
T1 - Concentrations of cytochrome p450 cholesterol side-chain cleavage enzyme and 3b-hydroxysteroid dehydrogenase during prostaglandin f2α-induced luteal regression in cattle
AU - Rodgers, R. J.
AU - Vella, C. A.
AU - Young, F. M.
AU - Tian, X. C.
AU - Fortune, J. E.
PY - 1995
Y1 - 1995
N2 - Prostaglandin F2α (PGF2α-induced regression of the corpus luteum causes both plasma progesterone concentrations and luteal concentrations of mRNA encoding the steroidogenic enzyme 3--hydroxysteroid dehydrogenase (3-HSD) to fall in parallel. To investigate the hypothesis that a decline in the concentrations of mRNA encoding steroidogenic enzymes causes plasma progesterone to fall, the luteal concentrations of the enzymes 3-HSD and cytochrome P450 cholesterol side-chain cleavage were measured during induced luteolysis. Holstein heifers were treated with PGF2α: (25 mg Lutalyse) on Day 6 or Day 7 of the oestrous cycle and corpora lutea were collected Oh, 2 h, 12 h, and 24 h later (n = 6, 4, 4, and 4 respectively). Analyses of the steroidogenic enzymes were carried out by Western immunoblotting. The luteal concentrations of both steroidogenic enzymes did not decrease over the 24-h period. It is concluded that, although the concentrations of mRNA encoding steroidogenic enzymes may decline in response to PGF2α, this does not lead to a sufficiently rapid reduction in the concentrations of the enzymes to precede, and thus cause, the decline in plasma progesterone concentrations. Thus, the mechanism for the initial decline in plasma progesterone concentrations during luteolysis is still not known.
AB - Prostaglandin F2α (PGF2α-induced regression of the corpus luteum causes both plasma progesterone concentrations and luteal concentrations of mRNA encoding the steroidogenic enzyme 3--hydroxysteroid dehydrogenase (3-HSD) to fall in parallel. To investigate the hypothesis that a decline in the concentrations of mRNA encoding steroidogenic enzymes causes plasma progesterone to fall, the luteal concentrations of the enzymes 3-HSD and cytochrome P450 cholesterol side-chain cleavage were measured during induced luteolysis. Holstein heifers were treated with PGF2α: (25 mg Lutalyse) on Day 6 or Day 7 of the oestrous cycle and corpora lutea were collected Oh, 2 h, 12 h, and 24 h later (n = 6, 4, 4, and 4 respectively). Analyses of the steroidogenic enzymes were carried out by Western immunoblotting. The luteal concentrations of both steroidogenic enzymes did not decrease over the 24-h period. It is concluded that, although the concentrations of mRNA encoding steroidogenic enzymes may decline in response to PGF2α, this does not lead to a sufficiently rapid reduction in the concentrations of the enzymes to precede, and thus cause, the decline in plasma progesterone concentrations. Thus, the mechanism for the initial decline in plasma progesterone concentrations during luteolysis is still not known.
UR - http://www.scopus.com/inward/record.url?scp=0029554507&partnerID=8YFLogxK
U2 - 10.1071/RD9951213
DO - 10.1071/RD9951213
M3 - Article
C2 - 8848589
AN - SCOPUS:0029554507
VL - 7
SP - 1213
EP - 1216
JO - Reproduction Fertility and Development
JF - Reproduction Fertility and Development
SN - 1031-3613
IS - 5
ER -