Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.24.3 (collagenase)
 18,340 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Adipocytes isolated from the epididymal fat of hypophysectomized rats by digestion with collagenase failed to respond to insulin with an increase in glucose utilization. These cells also exhibited an anomalous response to insulin when added in the presence of epinephrine. While insulin antagonized the lipolytic actions of epinephrine in normal adipocytes or in segments of epididymal fat from normal or hypophysectomized rats, it potentiated lipolysis in adipocytes isolated from hypophysectomized rats. This anomalous effect was also evident when isoproterenol, ACTH, or glucagon was used as the lipolytic agent, but the expected antilipolytic response was obtained when theophylline served as the lipolytic agonist. The lipolytic effects of insulin were not seen until 4-7 days after hypophysectomy. Treatment of hypophysectomized rats with a combination of GH (100 micrograms/rat . day), cortisone acetate (1 mg/rat . day), and T3 (1 micrograms/rat . day) for 5 days restored the antilipolytic response to insulin in cells of hypophysectomized rats, but no one hormone alone was effective. The data indicate that adipocytes of hypophysectomized rats retain their ability to recognize and response to insulin, but the ability of insulin to stimulate glucose oxidation or antagonize epinephrine-induced lipolysis is abolished by the cell isolation procedure. The findings underscore the need to consider the impact of hormonal status on the ability of cells to retain normal responsiveness during the rigors of the cell isolation procedure and suggest that failure to do so might lead to erroneous interpretations of the physiological actions of hormones.
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PMID:Lipolytic effects of insulin in adipocytes isolated from hypophysectomized rats. 627 27

Annulus fibrosus (AF) damage commonly occurs due to intervertebral disc (IVD) degeneration/herniation. The dynamic mechanical role of the AF is essential for proper IVD function and thus it is imperative that biomaterials developed to repair the AF withstand the mechanical rigors of the native tissue. Furthermore, these biomaterials must resist accelerated degradation within the proteolytic environment of degenerate IVDs while supporting integration with host tissue. We have previously reported a novel approach for developing collagen-based, multi-laminate AF repair patches (AFRPs) that mimic the angle-ply architecture and basic tensile properties of the human AF. Herein, we further evaluate AFRPs for their: tensile fatigue and impact burst strength, IVD attachment strength, and contribution to functional spinal unit (FSU) kinematics following IVD repair. Additionally, AFRP resistance to collagenase degradation and cytocompatibility were assessed following chemical crosslinking. In summary, AFRPs demonstrated enhanced durability at high applied stress amplitudes compared to human AF and withstood radially-directed biaxial stresses commonly borne by the native tissue prior to failure/detachment from IVDs. Moreover, FSUs repaired with AFRPs and nucleus pulposus (NP) surrogates had their axial kinematic parameters restored to intact levels. Finally, carbodiimide crosslinked AFRPs resisted accelerated collagenase digestion without detrimentally effecting AFRP tensile properties or cytocompatibility. Taken together, AFRPs demonstrate the mechanical robustness and enzymatic stability required for implantation into the damaged/degenerate IVD while supporting AF cell infiltration and viability.
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PMID:Angle-ply biomaterial scaffold for annulus fibrosus repair replicates native tissue mechanical properties, restores spinal kinematics, and supports cell viability. 2858 86