Alteration of Protein Kinase C Activity in Diabetic Rat Prostate

Garcia-Paramio, Pilar; Carmena, Marı́a J.; Gutierrez-Ocaña, M.T.; Recio, M.N.; Prieto, Juan Carlos

doi:10.1006/bbrc.1993.2025

Cited by 12 publications

(3 citation statements)

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“…At present, we have no exper imental evidence to support such a speculation, but PKC has been shown to be significantly activated in a variety of tissues o f diabetic rats [38][39][40][41], It should be noted that in diabetic rat aortas, there is a striking similarity between the enhanced contractile re sponses to 5-HT and PDBu: (1) both of the enhanced responses were eliminated in the presence of nifedipine, and (2) the contractile responses of rat aortas to 5-HT appeared to be completely dependent on PKC activation. Staurosporine at a concentration of 20 nM caused a com plete inhibition of 5-HT-induced contractions in control and diabetic aortas.…”

Section: Indices O F Arterial Compliance At Operational Pressurementioning

confidence: 99%

Enhanced 5-HT2 Receptor Mediated Contractions in Diabetic Rat Aorta: Participation of Ca2+Channels Associated with Protein Kinase C Activity

Hattori

Kawasaki²,

Kanno³

et al. 1995

J Vasc Res

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The aim of this study was to determine how the contractile responses to 5-hydroxytryptamine (5-HT) are altered in aortas from rats with streptozotocin-induced diabetes and to explore the possible mechanisms of the altered vascular reactivity to 5-HT in diabetes. In the presence of extracellular Ca²⁺ (2.5 mM), the contractile responses to stimulation of 5-HT₂ receptors with 5-HT were greater in aortas from diabetic rats as compared with those from age-matched controls. Similarly, phorbol-12, 13-dibutyrate (PDBu) (≧30 nM) induced significantly greater contractions in diabetic aortas. The enhanced contractile responses of diabetic aortas to 5-HT and PDBu were abolished in the presence of 1 µM nifedipine. Pretreatment with 20 nM staurosporine caused a complete inhibition of the contractile responses to 5-HT in both control and diabetic aortas. In contrast to those to 5-HT and PDBu, the contractile responses to high K⁺ (40 mM) were markedly diminished in diabetic aortas. The nifedipine-sensitive uptake of ⁴⁵Ca²⁺ induced by 5-HT was significantly greater in diabetic aortas than in controls, whereas that induced by high K⁺ was significantly less in diabetics. The phasic contractions produced by 5-HT in Ca²⁺-free medium were significantly attenuated in diabetic aortas, but those produced by norepinephrine were unchanged. Accumulation of [³H]inositol monophosphate (IP₁) in aortic strips prelabeled with myo-[³H] inositol was increased to a similar extent by 5-HT and norepinephrine in control rats, but the 5-HT-induced increase in [³H]IP₁ accumulation was significantly less than the norepinephrine-induced one in diabetics. These findings indicate that the extracellular Ca²⁺-dependent contractions mediated by 5-HT₂ receptors are enhanced in aortas from diabetic rats, and this is presumably related to a greater influx of Ca²⁺ through transmembrane Ca²⁺ channels as a consequence of increased protein kinase C activated processes. On the other hand, the contraction induced by release of Ca²⁺ from intracellular stores in response to 5-HT is diminished in these tissues, possibly due to the impaired phosphoinositide response.

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Section: Indices O F Arterial Compliance At Operational Pressurementioning

confidence: 99%

Enhanced 5-HT2 Receptor Mediated Contractions in Diabetic Rat Aorta: Participation of Ca2+Channels Associated with Protein Kinase C Activity

Hattori

Kawasaki²,

Kanno³

et al. 1995

J Vasc Res

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“…It has been reported that PKC translocates from the cytoplasm to membranes in diabetic cells (Garcia-Paramio et al 1993;Nagy et al 1991). PKC activity and immunoreactivity is increased in the membrane fractions of soleus muscle from hyperinsulinemic type II diabetic GotoKakizaki rats (Avignon et al 1996).…”

Section: Discussionmentioning

confidence: 99%

“…Changes in PKC isoforms have been demonstrated in many diabetic cells including rat hepatocytes (Inoguchi et al 1991), diabetic aorta and heart (Tang et al 1993), and diabetic prostate (Garcia-Paramio et al 1993). It has been reported that, in diabetic cells, PKC translocates from the cytoplasm to membrane fractions (Garcio-Paramio et al 1993;Nagy et al 1991).…”

Section: Introductionmentioning

confidence: 95%

Localization of protein kinase C in normal and galactosemic bovine lens epithelial cells in culture

Gonzalez-Charneco

Takemoto

1998

Histochemistry and Cell Biology

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The localization of the two major isoforms of protein kinase C (PKC), PKCalpha and PKCgamma, present in normal and galactosemic bovine lens epithelial cells in culture, was determined using PKC isoform-specific antisera and visualized with FITC-conjugated secondary antisera. The results indicated that the localization of PKC changed upon exposure to 40 mM galactose after 1 day. The subcellular distribution of control cells was cytoplasmic and perinuclear for PKCalpha, while, in 40 mM galactose-treated cells, PKCalpha was also localized to nuclei. In contrast, upon exposure to 40 mM galactose the PKCgamma of the lens epithelial cells was observed in nucleoli. These results suggest that the subcellular distribution of the PKC isoforms in bovine lens epithelial cells differs and is altered upon exposure to 40 mM galactose.

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