Purification, partial characterization, and development of a specific radioimmunoassay for goat placental lactogen
| Autor: | G. G. Ignotz, C. E. Card, F. J. Michel, W. B. Currie |
|---|---|
| Rok vydání: | 1990 |
| Předmět: |
Embryology
medicine.medical_specialty Amniotic fluid Somatotropic cell Ion chromatography Radioimmunoassay Biology Gel permeation chromatography Andrology Radioligand Assay Endocrinology Pregnancy Internal medicine medicine Animals Placental lactogen Gel electrophoresis Goats Obstetrics and Gynecology Cell Biology Placental Lactogen Prolactin Reproductive Medicine Growth Hormone Pregnancy Animal Electrophoresis Polyacrylamide Gel Female Isoelectric Focusing |
| Zdroj: | Reproduction. 90:25-36 |
| ISSN: | 1741-7899 1470-1626 |
| DOI: | 10.1530/jrf.0.0900025 |
| Popis: | Placental lactogen (PL) was isolated from goat cotyledonary tissue by a combination of mild alkaline extraction, anion and cation exchange chromatography, chromatofocussing and molecular filtration. The product, enriched 15,000-fold from the initial extract, was homogeneous when examined by SDS-gel electrophoresis (Mr 22,500) and isoelectricfocussing indicated a pI of 8.35 with a trace contaminant of pI 8.0. When assessed by relative binding activity in radioreceptor assays (RRA), goat PL exhibited somatotropic activity equivalent to 2.2 units/mg dry weight and lactogenic activity equivalent to 28.5 units/mg. A radioimmunoassay (RIA) for goat PL is described that is highly sensitive (190 pg/tube) and has acceptable repeatability within and between assays (6 and 13%, respectively). The assay is not affected by goat pituitary extracts or partly purified goat growth hormone and prolactin. Despite the marked increase in sensitivity of the RIA over that previously available when goat PL was measured by RRA, the hormone was not detected in jugular plasma of goats before Day 44 of pregnancy; concentrations increased thereafter and highest levels were measured during the last third of pregnancy in animals bearing triplets. Measurements by RIA are in general agreement with those obtained earlier in several studies in which RRAs were used. The hormone was detected in amniotic fluid. Maternal concentrations of goat PL declined before parturition and were undetectable by 18 h post partum. |
| Databáze: | OpenAIRE |
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