Adenosine 3′,5′-Monophosphate-Dependent Protein Kinase and Granulosa Cell Responsiveness to Gonadotropins*

Endocrinology ◽  
1984 ◽  
Vol 114 (6) ◽  
pp. 2190-2198 ◽  
Author(s):  
JOANNE S. RICHARDS ◽  
MARI HADDOX ◽  
JOSEPH S. TASH ◽  
ULRICH WALTER ◽  
SUZANNE LOHMANN
Keyword(s):  
Protein Kinase ◽  
Granulosa Cell ◽  
Dependent Protein Kinase ◽  
Dependent Protein

ACTIVATION INDUCED BY LUTEINIZING HORMONE OF TYPE II PROTEIN KINASE DEPENDENT ON CYCLIC ADENOSINE MONOPHOSPHATE AND PHOSPHORYLATION OF SOLUBLE PROTEINS IN PORCINE GRANULOSA CELLS

1980 ◽  
Vol 84 (1) ◽  
pp. 49-63 ◽  
Author(s):  
D. H. HALPREN-RUDER ◽  
R. A. JUNGMANN ◽  
W. J. GEORGE ◽  
J. R. JETER
Keyword(s):  
Protein Kinase ◽  
Luteinizing Hormone ◽  
Cyclic Amp ◽  
Granulosa Cell ◽  
Granulosa Cells ◽  
Type Ii ◽  
Dependent Protein Kinase ◽  
Porcine Granulosa Cells ◽  
Dependent Protein ◽  
Dose Dependent

The present experiments were designed to study whether exogenous LH could elicit acute cyclic AMP-mediated activation of cyclic AMP-dependent protein kinase and phosphorylation of cellular protein in intact porcine granulosa cells. Incubation of porcine granulosa cells (from 3 to 5 mm diameter follicles) with 2 μg luteinizing hormone/ml (LH) caused a significant rise of cellular cyclic AMP content within 2 min of the addition of LH. The increase was dose-dependent and occurred between doses of 0·2 and 2·0 μg LH/ml. Luteinizing hormone also caused a time- and dose-dependent dissociation of the type II cyclic AMP-dependent protein kinase isozyme in porcine granulosa cells. Luteinizing hormone (0·05–2 μg/ml) significantly dissociated the cyclic AMP-dependent protein kinase between 2 and 30 min after stimulation. The protein kinase dissociation was a specific effect of LH and was not elicited by either adrenocorticotrophic hormone or prolactin. During the period of LH-induced protein kinase activation, several soluble granulosa cell proteins, ranging in molecular weights from about 43 000 to 99 000, became phosphorylated in a time-dependent and hormone-specific manner. The results suggest that cyclic AMP-mediated activation of granulosa cell type II cyclic AMP-dependent protein kinase may be a prerequisite in the short-term molecular action of LH leading to LH-specific phosphorylation of several soluble granulosa cell proteins of an as yet unidentified function.

scholarly journals Hormone-induced intercellular signal transfer dissociates cyclic AMP-dependent protein kinase.

1984 ◽  
Vol 98 (5) ◽  
pp. 1710-1719 ◽  
Author(s):  
S A Murray ◽  
W H Fletcher
Keyword(s):  
Protein Kinase ◽  
Cell Membrane ◽  
Gap Junctions ◽  
Granulosa Cell ◽  
Cell Fusion ◽  
Granulosa Cells ◽  
Signal Transfer ◽  
Dependent Protein Kinase ◽  
Ovarian Granulosa Cells ◽  
Dependent Protein

We used co-cultures of porcine ovarian granulosa cells and mouse adrenocortical tumor cells (Y-1) to examine the kinetics of contact-dependent intercellular signal transfer and to assess the molecular mechanisms employed by this process. Exposure to follicle-stimulating hormone (FSH) caused cAMP-dependent protein kinase dissociation in granulosa cells and, with time, in Y-1 cells if, and only if, they contacted a responding granulosa cell. Y-1 cells close to a granulosa cell but not touching it failed to respond similarly. In reciprocal experiments, co-cultures were stimulated with adrenocorticotropic hormone (ACTH). Y-1 cells dissociated protein kinase as did granulosa cells in contact with Y-1 cells; however, granulosa cells that were not in contact with Y-1 cells failed to respond to the hormone. Fluorogenic steroids were secreted by Y-1 cells cultured alone and stimulated with ACTH, but were not secreted by cultures exposed to FSH. Neither hormone caused fluorogenic steroid production by granulosa cells. On the other hand these steroids were secreted in co-cultures stimulated with ACTH and to a lesser degree in co-cultures exposed to FSH. Autoradiography revealed that I125-FSH bound only to granulosa cells, never to Y-1 cells, even if they were in contact with an ovarian cell. The possibility of cell fusion was tested by experiments in which Y-1 cell membranes were labeled with cationized ferritin. These cells were then placed in co-culture with ovarian granulosa cells that had previously been allowed to ingest latex spheres. At regions of gap junctions between Y-1 and granulosa cells ferritin remained attached to the adrenal cell membrane and was never observed to migrate to the granulosa cell membrane. From these data, we conclude that hormone specific stimulation of one cell type leads to protein kinase dissociation in heterotypic partners only if they contact a hormone responsive cell. This signal transfer is bidirectional, exhibits temporal kinetics and occurs in the absence of apparent cell fusion. The only structural feature connecting Y-1 and granulosa cells were gap junctions implying they provided the communication channels; however, alternative mechanisms cannot be excluded. We have not established the identity of the signal being transferred although cAMP is a logical candidate.

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