Distribution and activation of protein kinase C in the rat testis tissue

Nikula, Hannu; Naor, Zvi; Parvinen, Martti; Huhtaniemi, Ilpo

doi:10.1016/0303-7207(87)90062-1

Cited by 53 publications

(30 citation statements)

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“…Similar effects caused by Ca 2+ have been reported for PKC in a number of tissues. PKC was also solubilized in the presence of chelating agents and remained associated with the particulate fraction in the presence of Ca 2+ (Nikula et al, 1987;Ikeda et al, 1996). In T. cruzi epimastigotes, Ogueta et al (1994Ogueta et al ( , 1996 have reported a Ca +2 /calmodulin (CaM)-dependent protein kinase (TcCaMK) the cellular distribution of which relied primarily on its phosphorylation state.…”

Section: Resultsmentioning

confidence: 99%

“…Interestingly, CK1-like and CK2-like activities have been previously shown in T. cruzi epimastigotes . Since divalent cations have been r e p o r t e d t o s t r o n g l y i n f l u e n c e t h e distribution of protein kinases and their substrates in other systems (Ikeda et al, 1996;Nikula et al, 1987;ClementChomienne & Walsh, 1996), we have studied here the effect of Ca 2+ and Mg 2+ on the solubilization of the CK2-like activity responsible for the phosphorylation of tubulin in T. cruzi.…”

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confidence: 99%

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Divalent cation hinder the solubilization of a tubulin kinase activity from Trypanosoma cruzi epimastigotes

Uzcanga¹,

Galán-Caridad²,

Noris-Suárez³

et al. 2003

Biol. Res.

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Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

Divalent cation hinder the solubilization of a tubulin kinase activity from Trypanosoma cruzi epimastigotes

Uzcanga¹,

Galán-Caridad²,

Noris-Suárez³

et al. 2003

Biol. Res.

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“…PKC, a key signaling system in many cell types, is known to be present in Leydig cells where it regulates testosterone biosynthesis (Nikula et al, 1987). PKC signaling is activated by arachidonic acid and the latter induces steroidogenic acute regulatory protein, leading to increased steroidogenesis (Janzen et al, 1976;Gudermann et al, 1992b).…”

Section: Discussionmentioning

confidence: 99%

“…An indirect mechanism is seen, for example, in the case of testosterone itself, which has been shown to decrease 11␤HSD oxidative activity and increase reductive activity (Gao et al, 1997). Both PKC and calcium signaling have been shown to regulate testosterone production (Janzen et al, 1976;Nikula et al, 1987;Gudermann et al, 1992b). Both PKC and calcium/ calmodulin modulators could affect 11␤HSD via the action of testosterone.…”

Section: Discussionmentioning

confidence: 99%

“…Because these hormones regulate Leydig cell function through more than one intracellular signal transduction pathway, including the cyclic adenosine monophosphate (cAMP)-dependent protein kinase A (PKA; Cooke, 1996), calcium (Janzen et al, 1976;Gudermann et al, 1992a,b), protein kinase C (PKC; Nikula et al, 1987;Majercik and Puett, 1991), and tyrosine protein kinase (Wuerther et al, 1995), 11␤HSD oxidation and reduction may be separately controlled. In the present investigation, after testing a series of modulators of PKA, calcium, PKC, and tyrosine protein kinase, we demonstrated that 11␤HSD oxidation and reduction in rat Leydig cells are controlled in opposing fashion by PKC and calcium-dependent signaling.…”

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Protein Kinase C Increases 11β‐Hydroxysteroid Dehydrogenase Oxidation and Inhibits Reduction in Rat Leydig Cells

Hardy

2002

Journal of Andrology

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ABSTRACT:Glucocorticoid hormone controls Leydig cell steroidogenic function through a receptor-mediated mechanism. The enzyme 11␤-hydroxysteroid dehydrogenase (11␤HSD) plays an important role in Leydig cells by metabolizing glucocorticoids, and catalyzing the interconversion of corticosterone (the active form in rodents) and 11-dehydrocorticosterone (the biologically inert form). The net direction of this interconversion determines the amount of biologically active ligand, corticosterone, available for glucocorticoid receptor binding. We hypothesize that 11␤HSD oxidative and reductive activities are controlled separately in Leydig cells, and that shifts in the favored direction of 11␤HSD catalysis provide a mechanism for the control of intracellular corticosterone levels. Therefore, in the present study, we tested the dependency of 11␤HSD oxidative and reductive activities on protein kinase C (PKC) and calcium-dependent signaling pathways. 11␤HSD oxidative and reductive activities were measured in freshly isolated intact rat Leydig cells using 25 nM radiolabeled substrates after treatment with protein kinase modulators. We found that PKC and calcium-dependent signaling had opposing effects on 11␤HSD oxidative and reductive activities. Stimulation of PKC using the PKC activator, 6-[N-decylamino]-4-hydroxymethylinole (DHI), increased 11␤HSD oxidative activity from a conversion rate of 5.08% to 48.23%with an EC 50 of 1.70 Ϯ 0.44 M (mean Ϯ SEM), and inhibited reductive activity from 26.90% to 3.66% conversion with an IC 50 of 0.22 Ϯ 0.05 M. This indicated that PKC activation in Leydig cells favors 11␤HSD oxidation and lower levels of corticosterone. The action of DHI was abolished by the PKC inhibitor bisindolylmaleimide I. In contrast, addition of calcium to Leydig cells increased 11␤HSD reductive activity while decreasing oxidative activity, thereby favoring reduction and conversion of inert 11-dehydrocorticosterone into active corticosterone. The opposite effect was seen after elimination of calciumdependent signaling, including removal of calcium by EGTA or addition of the calmodulin (calcium binding protein) inhibitor SKF7171A, or the calcium/calmodulin-dependent protein kinase I (CaMK II) inhibitor, KN62. We conclude that 11␤HSD oxidative and reductive activities are separately regulated and that, in contrast to calcium-dependent signaling, PKC stimulates 11␤HSD oxidation while inhibiting 11␤HSD reduction. Maintenance of a predominantly oxidative 11␤HSD could serve to eliminate adverse glucocorticoid-induced action in Leydig cells.

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Apoptosis Pattern Elicited by Several Apoptogenic Agents on the Seminiferous Epithelium of the Adult Rat Testis

BLANCO‐RODRÍGUEZ,

MARTÍNEZ‐GARCÍA

1998

Journal of Andrology

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Spontaneous germ cell death during spermatogenesis is an important event, and the usefulness of the seminiferous epithelium as an in vivo model to study apoptosis has been evidenced. Nevertheless, the response of the testis to apoptogenic agents has not been analyzed. This study was designed to determine germ cell sensitivity to induction of apoptosis and to provide baseline data on the testis response to several apoptogenic agents. Induced apoptosis was assessed by in situ DNA 3′‐end labeling and quantified at every stage of the spermatogenic cycle. The shortest response time for every agent was established based on morphological and quantitative criteria. Our results show significantly increased incidence of germ cell deaths after all treatments, mainly at stages I, XII, and XIV. These specific stages coincide with those at which the greatest numbers of spontaneous germ cell deaths occur in control animals. Moreover, the rapid and highly specific response of germ cells to all the apoptogenic agents used in the present study indicate that apoptosis must be tightly regulated at these stages of the seminiferous epithelium. As a consequence, we propose that the disruption of apoptosis control might be an important determinant for idiopathic male infertility.

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Distribution and activation of protein kinase C in the rat testis tissue

Cited by 53 publications

References 31 publications

Divalent cation hinder the solubilization of a tubulin kinase activity from Trypanosoma cruzi epimastigotes

Divalent cation hinder the solubilization of a tubulin kinase activity from Trypanosoma cruzi epimastigotes

Protein Kinase C Increases 11β‐Hydroxysteroid Dehydrogenase Oxidation and Inhibits Reduction in Rat Leydig Cells

Apoptosis Pattern Elicited by Several Apoptogenic Agents on the Seminiferous Epithelium of the Adult Rat Testis

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