Abstract
Fibroblast cultures from human fetuses (12-14 wk), neonates, amniotic fluid, and older children were examined for insulin-1125 binding. In addition, studies were made of fetal and neonatal cell cultures for growth rate and density at confluence. Synthesis of protein, DNA, and RNA and intracellular content of cAMP were measured in cell cultures under the following conditions: a) immediate refeeding of confluent cultures with medium containing 20% fetal calf serum (FCS) or serum-free medium containing 10−9M or 10−6M insulin; b) similar refeeding of log-phase cultures after 24 hr. maintenance in serum-free media. Fetal cells have less than 10% of the net insulin binding capacity and none of the high-affinity binding sites (10−10, 10−9M) observed with fibroblasts from neonates and older children. Metabolic response correlates with high-affinity binding sites. Fetal flbroblast cultures grow more rapidly and to greater densities than cultures from neonates. At confluence and after serum-deprivation, fetal cells are unresponsive to insulin, whereas cells from neonates respond to insulin in a dose-related manner. However, this response is insignificant when compared to that with medium containing FCS. The findings suggest that the appearance of insulin binding sites and metabolic response to insulin in vivo takes place sometime after 14 wks. gestation.
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Handelsman, D., Nakagawa, S. & Nitowsky, H. THE ONTOGENY OF RECEPTORS AND RESPONSIVENESS TO INSULIN IN HUMAN CELL CULTURES. Pediatr Res 8, 357 (1974). https://doi.org/10.1203/00006450-197404000-00101
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DOI: https://doi.org/10.1203/00006450-197404000-00101