Phenotypic diversity of the cellular 1,25-dihydroxyvitamin D3-receptor interaction among different genera of New World primates.

High serum of 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] concentrations and target organ resistance to the hormone are characteristic findings in some New World primates (platyrrhines). We examined the abilities of cultural dermal fibroblasts from individual platyrrhines of four different genera, Aotus, Alouatta, Pithecia, and Saguinus, to internalize and respond to 1,25-(OH)2D3 in an attempt to identify possible phenotypic heterogeneity in the 1,25-(OH)2D3-receptor interaction among them. Results were compared to those from two Old World primates (catarrhines), Pan troglodytes and Pongo pygmaeus. Compared to catarrhine cells, cells from Alouatta, Pithecia, and Saguinus demonstrated 1) a 10-fold decrease in [3H] 1,25-(OH)2D3 internalization capacity; 2) a 2- to 5-fold increase in the apparent internalization constant [3H]1,25-(OH)2D3; and 3) a 3- to 15-fold increase in the 1,25-(OH)2D3 concentration required to elicit half-maximal induction of [3H]25-hydroxyvitamin D3-24-hydroxylating activity (ED50; rank order Sanguinus much greater than Pithecia greater than Alouatta). Although the internalization capacity of cells from two different primates in the genus Aotus was 3- to 4-fold lower than that in catarrhine cells, the internalization constant for hormone and ED50 for 24-hydroxylating activity were similar. These data suggest that the functional 1,25-(OH)2D3-receptor phenotype of the owl monkey, Aotus trivirgatus, is more closely aligned to the catarrhine phenotype than are those of other platyrrhines in the families Cebidae and Callitricidae.