title: Sexual dimorphism in the contribution of protein kinase C isoforms to nociception in the streptozotocin diabetic rat.
abstract: The contribution of second messenger signaling, glucose level and sex hormones to sexual dimorphism in the streptozotocin model of diabetic painful peripheral neuropathy was evaluated. Streptozotocin induced elevation of blood glucose and mechanical hyperalgesia (measured by the Randall-Selitto paw-withdrawal test) were both greater in female rats. Ovariectomy abolished and estrogen implants reconstituted this sexual dimorphism; gonadectomy in males had no effect. An inhibitor of protein kinase Cepsilon attenuated hyperalgesia in males and ovariectomized females, but not in normal females or in ovariectomized females with estrogen implants, whereas inhibitors of protein kinase Cdelta attenuated hyperalgesia in females but not in males. Inhibitors of protein kinase A, protein kinase C (non-selective), protein kinase G and nitric oxide synthase attenuated hyperalgesia equally in both sexes. Higher blood glucose levels in diabetic females were also sex hormone dependent, and magnitude of hyperalgesia correlated with blood glucose level in diabetic male and female rats. These results demonstrate sexual dimorphism in diabetic hyperalgesia, mediated by sex hormone dependent differences in protein kinase Cepsilon and protein kinase Cdelta signaling and blood glucose levels and suggest that sex may be an important factor to be considered in the treatment of symptomatic diabetic neuropathy.
authors.affiliation: Department of Medicine, Division of Neuroscience and Biomedical Sciences Program and UCSF-NIH Pain Center, Box 0440/Room C522, 521 Parnassus Avenue, University of California, San Francisco, CA 94143-0440, USA. aley@itsa.ucsf.edu
authors.forename: E K
authors.initials: EK
authors.lastname: Joseph
authors.forename: J D
authors.initials: JD
authors.lastname: Levine
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents; D001786:Blood Glucose / Q000187:drug effects; D001835:Body Weight / Q000187:drug effects; D002369:Castration / Q000379:methods; D003921:Diabetes Mellitus, Experimental / Q000139:chemically induced / Q000201:enzymology* / Q000378:metabolism / Q000503:physiopathology; D003929:Diabetic Neuropathies / Q000139:chemically induced / Q000503:physiopathology; D004195:Disease Models, Animal; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004967:Estrogens / Q000008:administration & dosage; D005260:Female; D006066:Gonads / Q000601:surgery; D006930:Hyperalgesia / Q000378:metabolism / Q000503:physiopathology; D008297:Male; D017288:Pain Threshold / Q000187:drug effects / Q000502:physiology; D020033:Protein Isoforms / Q000378:metabolism*; D011493:Protein Kinase C / Q000378:metabolism*; D051381:Rats; D012727:Sex Characteristics; D013311:Streptozocin
chemical_list: D000900:Anti-Bacterial Agents; D001786:Blood Glucose; D004791:Enzyme Inhibitors; D004967:Estrogens; D020033:Protein Isoforms; D013311:Streptozocin; D011493:Protein Kinase C