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Differential secretion of follicle-stimulating hormone and luteinizing hormone from ovine pituitary cells following activation of protein kinase A, protein kinase C, or increased intracellular calcium.
- Source :
-
Biology of reproduction [Biol Reprod] 1994 Jan; Vol. 50 (1), pp. 49-54. - Publication Year :
- 1994
-
Abstract
- A higher dose of GnRH is required to stimulate release of FSH than of LH, both in vivo and in vitro. Therefore, we tested the hypothesis that secretion of FSH may be mediated via a second messenger pathway different from the one that modulates secretion of LH. Pituitary cells from intact ewes were cultured in suspension in DMEM plus 10% wether serum. After 18 h, cell were washed and challenged for 2 h with agents capable of activating protein kinase A (dibutyryl cAMP), protein kinase C (phorbol 12-myristate 13-acetate; PMA), or increasing intracellular calcium (the calcium ionophore A23187). GnRH (0.01-10 nM) and PMA (0.2-20 nM) stimulated dose-dependent increases in secretion of LH. FSH secretion also was stimulated by GnRH and PMA; however, the percentage of total cellular FSH released was lower (p < 0.05) than the percentage of total cellular LH released. Dibutyryl cAMP (10 mM) induced a modest release (p < 0.05) of both LH and FSH. A23187 (1-10 microM) stimulated secretion of LH in a dose-dependent manner but did not influence secretion of FSH; however, GnRH- and PMA-induced secretion of FSH required the presence of intracellular calcium. On the basis of the results of this study, we suggest that secretion of FSH is less than secretion of LH following direct activation of these second messenger systems. Furthermore, we suggest that in contrast to the situation for LH, increased intracellular calcium is not the primary stimulus for inducing secretion of FSH.
- Subjects :
- Animals
Bucladesine pharmacology
Calcimycin pharmacology
Cyclic AMP-Dependent Protein Kinases metabolism
Enzyme Activation drug effects
Female
Gonadotropin-Releasing Hormone pharmacology
Pituitary Gland drug effects
Pituitary Gland enzymology
Protein Kinase C metabolism
Tetradecanoylphorbol Acetate pharmacology
Calcium metabolism
Follicle Stimulating Hormone metabolism
Luteinizing Hormone metabolism
Pituitary Gland metabolism
Protein Kinases metabolism
Sheep physiology
Subjects
Details
- Language :
- English
- ISSN :
- 0006-3363
- Volume :
- 50
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- Biology of reproduction
- Publication Type :
- Academic Journal
- Accession number :
- 8312450
- Full Text :
- https://doi.org/10.1095/biolreprod50.1.49