Involvement of Distinct Signaling Pathways in Activin-Induced Increases in FSH Secretion and Enlargement of FSH Cell Population in the Rat Pituitary
Autor: | Haruto Kuroda, Hisako Kyan, Michiko Nakashima, Emilliana Y. Rahayu, Noboru Murakami, Tetsuro Katayama |
---|---|
Rok vydání: | 2000 |
Předmět: |
endocrine system
medicine.medical_specialty Endocrinology Diabetes and Metabolism Cell Population Biology Nicardipine chemistry.chemical_compound Endocrinology Anterior pituitary Antibody Specificity Pituitary Gland Anterior 1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine Internal medicine Ca2+/calmodulin-dependent protein kinase medicine Animals Humans Inhibins Channel blocker Growth Substances education Cells Cultured education.field_of_study Dose-Response Relationship Drug Cell Differentiation Calcium Channel Blockers Activins Rats Mitotic inhibitor medicine.anatomical_structure Bromodeoxyuridine chemistry Calcium Channels Follicle Stimulating Hormone Signal transduction Thymidine hormones hormone substitutes and hormone antagonists Signal Transduction |
Zdroj: | Endocrine Journal. 47:239-247 |
ISSN: | 1348-4540 0918-8959 |
Popis: | Activin-A induces increases in FSH secretion, as well as the number of immunoreactive FSH cells, in cultured rat pituitary cells. In this study, we examined whether mechanisms involved in these two actions of activin-A are identical or not, with respect to the involvement of cellular proliferation and of Ca2+-dependent signaling pathways. Treatment with activin-A (25 ng/ml) for 48 h caused increases in the number of cultured rat anterior pituitary cells that incorporated BrdU, a thymidine analog. The stimulatory effects of activin-A on FSH secretion and on the percentage of immunoreactive FSH cells were, however, not inhibited by the presence of the mitotic inhibitor cytosine arabinoside. On the other hand, the stimulatory effect of activin-A on the percentage of immunoreactive FSH cells was completely blocked in the presence of the Ca2+/calmodulin kinase inhibitor KN-62 or the L-type Ca2+ channel blocker nicardipine. Neither of these inhibitors, however, revealed significant influence on the effect of activin-A on FSH secretion. These results suggest that activin-A exhibits its dual effect on FSH cells without causing cellular proliferation. Furthermore, activin-A appears to induce increases in FSH secretion and enlargement of FSH cell population through distinct intracellular signaling pathways, the former through Ca2+-independent and the latter through Ca2+-dependent mechanisms. |
Databáze: | OpenAIRE |
Externí odkaz: |