Evidence that Most of the Radioimmunoassayable Inhibin Secreted by the Corpus Luteum of the Common Marmoset Monkey is of a Non-Dimeric Form1
| Autor: | Shanthi Muttukrishna, N Groome, G E Webley, Philip G. Knight |
|---|---|
| Rok vydání: | 1992 |
| Předmět: |
endocrine system
medicine.medical_specialty Immunoradiometric assay biology Marmoset Early pregnancy factor Ovary Cell Biology General Medicine Luteal phase Ovarian cycle medicine.anatomical_structure Endocrinology Reproductive Medicine Internal medicine biology.animal medicine biology.protein Bioassay Corpus luteum reproductive and urinary physiology hormones hormone substitutes and hormone antagonists |
| Zdroj: | Biology of Reproduction. 47:554-560 |
| ISSN: | 1529-7268 0006-3363 |
| Popis: | Although recent data for several species of prinsate, including human and marmoset, indicate that the corpus luteum secretes high levels of radioimmunoassayable inhibin, the nature of the immunoreactive (if) inhibin detected has not been established. In this study, plasma ir-inhibin levelsduring the ovarian cycle of the marmoset (n = 12 animals) were measured by a-subunitdirected inhibits RIA, and values were compared with those estimated by a recently developed two-site Immunoradiometric assay (IRMA) specific for inhibin a-� darner. Consistent with earlier data, plasma levels of ir-inhibin measured by RIA (overall mean value 133 ± 7 ng/ml; n = 171) reached values 4-fold higher (p < 0.001) durIng the luteal phase (222 ± 20 ng/ml) than during the fofficular phase (58 ± 8 ng/ml), being directly correlated with plasma progesterone levels (r = 0.65;p < 0.001). In contrast, plasma ir-Inhibin levels estimated by IRMA were substantially lower than those measured by lIlA (overall mean value 9.62 ± 1.08 ng/ml; n = 171) and did not vary significantly during the cycle. Administration of a luteolytic dose of cloprostenol during the late luteal phase/early pregnancy led to an abrupt fall in plasma concentrations of progesterone (95%) and a-inhibits measured by MA (82%), whereas dimeric inhibin levels remained unchanged. Analysis of marmoset luteal extracts (n = 5) by RIA, IRMA, and inhibin bioassay yielded inhibln estimates of 102.6 ± 21.0, 0.632 ± 0.103, and < 2.0 ng/mg, respectively, thus confirming that only a very small proportion of the Inhibin produced was dimeric (i.e., bioactive) in nature. These findings have Important Implications for the physiological interpretation of inhibin lIlA data, particularly wIth regard to the suggestion that In primates inhlbin of luteal origin contributesto the ovarian feedback suppression of pituitary FSH secretion. |
| Databáze: | OpenAIRE |
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