Qualitative Change in Gonadotropin during Normal Aging in the Male Rat*
| Autor: | Colleen McNAMARA, P. Michael Conn, Lisa Shoenhardt, Deloris C. Rogers, Ralph L. Cooper |
|---|---|
| Rok vydání: | 1980 |
| Předmět: |
Male
Testosterone propionate Aging medicine.medical_specialty medicine.drug_class Normal aging Biology Gonadotropin preparations chemistry.chemical_compound Sex Factors Endocrinology Internal medicine medicine Animals Testosterone Luteinizing Hormone Rats Sialic acid chemistry Pituitary Gland Chromatography Gel biology.protein Female Gonadotropin Neuraminidase N-Acetylneuraminic acid |
| Zdroj: | Endocrinology. 106:1549-1553 |
| ISSN: | 1945-7170 0013-7227 |
| DOI: | 10.1210/endo-106-5-1549 |
| Popis: | In the present work we have compared a pituitary LH extract and circulating LH from adult male rats (5 months old) with those from rats 10, 13, or 24 months old. The pituitary and circulating forms of LH prepared from old animals had a higher apparent molecular weight, judged by gel filtration, than LH preparations from younger animals. This difference may be due to increased sialic acid content of the larger form, since simultaneous neuraminidase treatment of this gonadotropin preparation and our internal reference standard ([125I]LH prepared from a normal adult rat) abolished the apparent size difference. In addition, the larger form prepared from old rats was cleared more slowly from the circulation of immature females than the form prepared from young rats. The apparent increase in sialation during normal aging could be mimicked in young animals which were castrated. Injections of testosterone propionate reversed the effect in both castrates and old animals. The data suggest that the diminished levels of metabolically active testosterone or other steroid metabolites in old male rats may result in qualitative alterations in the stored and released forms of LH. |
| Databáze: | OpenAIRE |
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