Premium
Bovine embryos produce a urokinase‐type plasminogen activator
Author(s) -
Berg Debra A.,
Menino Alfred R.
Publication year - 1992
Publication title -
molecular reproduction and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.745
H-Index - 105
eISSN - 1098-2795
pISSN - 1040-452X
DOI - 10.1002/mrd.1080310104
Subject(s) - biology , plasminogen activator , embryo , urokinase , microbiology and biotechnology , andrology , genetics , medicine
Abstract The type of plasminogen activator (PA) secreted by bovine embryos was identified. Day 12–14 embryos were collected from estrus‐synchronized, superovulated, and naturally mated crossbred beef cows. Embryos were left intact (E) or microdissected into component embryonic discs (ED) and trophoblastic vesicles (TV). Intact embryos, ED, and TV were pre‐cultured for 2 days in Minimum Essential Medium Alpha (MEMα) with 10% heat‐inactivated fetal calf serum, washed in serum‐free MEMα, and cultured individually for 5 days in 50 μl microdrops of MEMα with 15 mg/ml bovine serum albumin. At 24 hr intervals, E, ED, and TV were observed for tissue morphology and transferred to fresh microdrops, and medium was recovered and frozen at −20°C. At the end of culture, blastocoelic fluid (BF) and embryonic tissues were recovered and frozen at −20°C. Plasminogen activator concentrations in medium, tissues, and BF were determined by using a caseinolytic assay. Antibodies to urokinase‐type PA (anti‐uPA) and tissue‐type PA (anti‐tPA), and the urokinase inhibitor, amiloride (AMR), were used to identify the type of PA produced by bovine embryonic tissues. Intact embryos and TV released more PA ( P < 0.05) than ED, and tissues exhibiting expanded blastocoels released less PA ( P < 0.05) than tissues with collapsed blastocoels. Blastocoelic fluid from TV exhibited more PA ( P < 0.05) activity than from ED. Treatment with anti‐uPA decreased PA activity ( P < 0.05) in pooled medium and tissues from E compared to treatment with nonspecific immunoglobulins and anti‐tPA. Amiloride completely eliminated PA activity ( P < 0.05) in tissues, medium, and BF. These results suggest that day 12–14 bovine embryos secrete a urokinase‐type PA.