Table 1.
Distribution of Golgi complex elements between surface and core of fibers from the soleus (SOL) and tensor fascia latae (TFL) muscles
| SOL | TFL | SOL/TFL | ||
|---|---|---|---|---|
| GC elements at fiber surface | Number of elements per 1000 μm2 | 38.3 ± 6.2 (n = 27) | 10.0 ± 3.4 (n = 14) | 3.8 |
| Number of elements around each nucleus | 13.2 ± 1.9 (n = 22) | 2.2 ± 0.5 (n = 26) | 6.5 | |
| GC elements in fiber core | Number of elements per 1000 μm3 | 1.7 ± 0.4 (n = 16) | 2.6 ± 0.8 (n = 15) | 0.6 |
| Fiber dimensions | Fiber cross-section (μm2) | 1480 | 2920 | 0.5 |
| Number of nuclei per 100 μm fiber length | 9.0 ± 3.0 (n = 18) | 13.9 ± 2.2 (n = 13) | 0.7 | |
| Cell volume per nucleus (μm3) | 16,444 | 21,007 | 0.8 | |
| GC estimates for a 100-μm-long fiber segment | Number of elements on the surface Number of elements on the surface (%) | 646 74 | 258 27 | 2.5 |
| Number of elements in the core Number of elements in the core (%) | 223 26 | 692 73 | 0.3 | |
| Total | 869 | 950 | 0.9 | |
| Total per nucleus | 96 | 68 | 1.4 |
Z-series of confocal images, each consisting of 10 images starting at the surface of the fiber, were recorded for each muscle (see Materials and Methods). The surface pattern was represented by the first image of each series, and the number of elements around each nucleus was counted from these images. The core pattern was represented by the maximum projection of the nine other images. The images were quantitated with NIH Image software. We used the “particle counting” function to count the number of GC elements. For core images, the result was divided by 9 to obtain the number of elements per single optical section. We used the confocal software to measure the dimensions of the fibers, which allowed us to calculate their cross-sectional area. The number of myonuclei was counted separately, by examining fibers double-stained with Hoechst and with anti-GLUT4 (see Materials and Methods for details). The numbers provided represent the mean, ± SD when appropriate. Similar results (±10%) were obtained when we measured the surface of the Golgi elements rather than their numbers, indicating that the average size of an element is conserved within fibers and between different muscles.