Luteolytic effect of LH: inhibition of 3 beta-hydroxysteroid dehydrogenase and stimulation of 20 alpha-hydroxysteroid dehydrogenase luteal activities in late pregnant rats
| Autor: | C O Stocco, Ricardo P. Deis |
|---|---|
| Rok vydání: | 1996 |
| Předmět: |
endocrine system
medicine.medical_specialty 3-Hydroxysteroid Dehydrogenases medicine.drug_class Endocrinology Diabetes and Metabolism Luteolysis Stimulation Ovary Luteal phase Biology Endocrinology Corpus Luteum Pregnancy Internal medicine medicine Animals Hydroxysteroid dehydrogenase Rats Wistar 20-Hydroxysteroid Dehydrogenases Progesterone Immune Sera Luteinizing Hormone medicine.disease Rats medicine.anatomical_structure Female Gonadotropin Corpus luteum |
| Zdroj: | The Journal of endocrinology. 150(3) |
| ISSN: | 0022-0795 |
| Popis: | The mechanisms associated with the onset of luteolysis in the pregnant rat are not well known. The effect of a specific rat LH antiserum (AS-rLH) and of ovine LH (oLH) on luteal steroidogenesis on day 19 of pregnancy was examined. Rat LH antiserum administered intrabursally at 1000–1100 h on day 19 of pregnancy prevented the physiological decrease in 3β-hydroxysteroid dehydrogenase (3β-HSD) activity, the increase in 20α-hydroxysteroid dehydrogenase (20α-HSD) activity and the fall in serum progesterone (P4) level observed at 1800 h on day 21 of pregnancy. To see if oLH has a direct effect on luteal steroidogenesis, the gonadotrophin was injected into the periovarian bursa. The intrabursa treatment with 1 μg oLH on day 19 of pregnancy at 0800–0900 h did not modify corpus luteal function 36 h after treatment, but treatment with 4 μg oLH per ovary induced a significant progressive decrease in luteal 3β-HSD activity starting 12 h after treatment, while a significant increase in 20α-HSD activity, concomitant with a decrease in serum P4 level, occurred 48 h after treatment. Luteal P4 content decreased with respect to control groups 36 and 48 h after intrabursal treatment with 4 μg oLH. The intrabursal administration of 8 μg oLH induced an increase in 20α-HSD activity and a decrease in 3β-HSD activity 36 h after treatment. Administration of 4 μg oLH per ovary on day 8 of pregnancy induced a significant increase in serum P4 levels without modifying 3β-HSD activity. In rats treated with oLH on day 19 of pregnancy the decrease in 3β-HSD activity occurred 36 h before the significant increase in 20α-HSD activity and serum P4 level. In conclusion, the luteal enzymatic activity changes and the significant decrease in the intraluteal P4 concentration induced by the intrabursal administration of oLH and the clear effect of AS-rLH preventing the physiological luteal changes preceding parturition provide good evidence of an intraovarian action of LH during the normal progression of luteolysis in late pregnant rats. Journal of Endocrinology (1996) 150, 423–429 |
| Databáze: | OpenAIRE |
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