Stimulation of matrix-metalloproteinase-1 and tissue inhibitor of metalloproteinase-1 gene expression in rats by the preovulatory prolactin peak.
Since structural luteolysis involves deterioration of tissue, the gene expression of matrix-metalloproteinase-1 (MMP-1) and the respective tissue inhibitor of this metalloprotease (TIMP-1) were measured at various times on the day of pro-oestrus and in animals in which the preovulatory prolactin surge was blocked for the duration of 3 cycles by bromocriptine. An additional group of prolactin-blocked rats received a prolactin replacement injection on the afternoon of pro-oestrus. In spontaneously pro-oestrous rats, MMP-1 and TIMP-1 gene expression increased significantly (P<0.01) prior to the occurrence of the preovulatory LH surge but simultaneously with the onset of the preovulatory prolactin surge. When prolactin release was blocked by bromocriptine for 3 cycles, no such changes were observed during the afternoon of pro-oestrus. However, an intraperitoneal injection of bovine prolactin at the time when the preovulatory prolactin surge occurs normally, increased MMP-1 and TIMP-1 gene expression (P<0.01). These results indicate that MMP-1 and TIMP-1 gene expression are stimulated by the preovulatory prolactin surge. Previous work has shown that the preovulatory LH surge activates the enzymatic cascade which leads to increased collagenase activity.
Hirsch
B
B
Department of Obstetrics and Gynecology, Division of Clinical and Experimental Endocrinology, University of Göttingen, Göttingen, Germany.
Knoke
I
I
Leonhardt
S
S
Pitzel
L
L
Jarry
H
H
Wuttke
W
W
D000818:Animals; D001971:Bromocriptine / Q000494:pharmacology; D017364:Collagenases / Q000235:genetics*; D005260:Female; D005498:Follicular Phase; D005786:Gene Expression Regulation / Q000187:drug effects*; D020781:Matrix Metalloproteinase 1; D010053:Ovary / Q000187:drug effects / Q000378:metabolism; D011388:Prolactin / Q000037:antagonists & inhibitors / Q000378:metabolism* / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000235:genetics*
D019715:Tissue Inhibitor of Metalloproteinase-1; D001971:Bromocriptine; D011388:Prolactin; D017364:Collagenases; D020781:Matrix Metalloproteinase 1