GROWTH-FACTORS (EGF, IGF-I) MODULATE THE MORPHOLOGICAL-DIFFERENTIATION OF ADULT MARMOSET (CALLITHRIX-JACCHUS) SERTOLI CELLS IN-VITRO

The effects of epidermal growth factor (EGF) and insulin-like growth f actor I (IGF-I) on mature marmoset (Callithrix jacchus) Sertoli cells in vitro were investigated using light and electron microscopic and hi stochemical means. The morphological data were substantiated by morpho metric analysis at the electron microscopic level. In a bicameral cham ber system, cultured Sertoli cells displayed a high degree of ultrastr uctural differentiation and exhibited a polarized appearance. Basally located tight junctions joined adjacent cells. Germ cells of early sta ges of development were regularly seen. Under the influence of IGF-I, cells developed extensive cell-cell contacts. The surface density of s mooth endoplasmic reticulum was increased. In contrast, the volume den sity of lipid inclusions was decreased. The morphological integrity of enclosed germ cells was maintained for a longer period. With EGF, cel ls were arranged in loose aggregates. Intercellular spaces were widene d. The volume density of lipid inclusions was increased. Germ cells ex hibited profound signs of degeneration early in culture, paralleled by increased development of phagolysosomes and high acid-beta-galactosid ase activity. Under the influence of either growth factor, mitochondri a displayed a shift from the crista to the tubulo-vesicular type. Mito chondrial dimensions and the volume density of mitochondrial compartme nt were increased. In comparison with control cultures all documented changes were statistically significant. Our findings indicate that mar moset Sertoli cells are target cells for EGF and IGF-I. Moreover, the dynamics of intercellular contacts, germ cell survival, and morphologi cal indices of lipid and/or steroid metabolism seem to be differential ly modulated.