Characteristics of retinol accumulation from serum retinol-binding protein by cultured sertoli cells

Journal Article · Tue Dec 12 00:00:00 EST 1989 · Biochemistry; (USA)

DOI:https://doi.org/10.1021/bi00451a015· OSTI ID:6970323

Shingleton, J L; Skinner, M K; Ong, D E ^[1]

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1. Vanderbilt Univ. School of Medicine, Nashville, TN (USA)

The uptake of retinol was examined in cultured Sertoli cells when retinol was provided as a complex with the transport protein retinol-binding protein (RBP). Sertoil cells accumulated ({sup 3}H)retinol in a time- and temperature-dependent manner. The change in rate of retinol accumulation occurred when the cells had accumulated approximately 0.53 pmol of retinol/{mu}g of cellular DNA. Extraction and HPLC analysis of the cell-associated radioactivity yielded retinol and retinyl esters, indicating that a significant proportion of the accumulated retinol was esterified. Excess unlabeled retinol-RBP competed with ({sup 3}H)retinol-RBP for ({sup 3}H)retinol delivery to the cells, indicating that RBP delivery of retinol was a saturable and competable process. However, free ({sup 3}H)retinol associated with Sertoli cells in a noncompetable manner. The transport constant for specific retinol accumulation from RBP was 3.0 {mu}M. Neither iodinated nor reductively methylated RBP was accumulated by or tightly bound to Sertoli cells. Competition studies indicated, however, that protein recognition is important in the retinol uptake process. RBP, CRBP, and CRBP(II) competed with ({sup 3}H)retinol-RBP for ({sup 3}H)retinol accumulation, but free retinol, retinol-bovine serum albumin, and retinol-{beta}-lactoglobulin did not. These studies indicated that Sertoli cell uptake of retinol involved recognition of the retinol-RBP complex at the cell surface with subsequent internalization of retinol, but not RBP.

• OSTI ID: 6970323
• Journal Information: Biochemistry; (USA), Vol. 28:25; ISSN 0006-2960
• Country of Publication: United States
• Language: English

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59 BASIC BIOLOGICAL SCIENCES
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