“…Our data are essentially similar to those of Kazazoglou et al (1983). These discrepancies between the B, data expressed in different units may be due largely to the following: (i) the ratio of 'mg protein/mg tissue' increases with age, i.e., 0.055 + 0.005 (n = 6) on day 16 post-gestation, 0.076 ± 0.003 (n = 13) on the day of birth, 0.111 + 0.004 (n = 12) on neonatal day 10, 0.123 + 0.006 (n = 11) on neonatal day 20, and 0.144 + 0.006 (n = 12) at adult ages of 2-3 months (the present data); (ii) the ratio of 'sarcolemmal protein/cell protein' or 'surface area/ fibre mass' decreases with age because of the development of intracellular organs (Baker & Potter, 1980;Whitsett & Darovec-Beckerman, 1981;Nedoma et al, 1986 (Kojima et al, 1988) are more similar to those of Iso-induced increases in Px (Kojima et al, 1990) (Kojima et al, 1990). This developmental time course correlates well with that of Ca2+ channels (present data) and of stimulatory GTP-binding (G,) proteins (Kojima et al, 1988).…”