Stimulation by N6, O2′-dibutyryl adenosine 3′,5′-cyclic-phosphate of amino acid transport, protein synthesis, and chondroitin sulfate synthesis in embryonic bone in vitro, contrasted with the effects of thyroid hormones

Abstract

Measurement were made of the effects of N 6,O 2′-dibutyryl adenosine 3′,5′-cyclic-phosphate on uptake and incorporation of amino acids and inorganic sulfate by intact pelvic bones of 10-day chick embryos. The N 6,O 2′-dibutyryl adenosine 3′,5′-cyclic-phosphate causes of 20–50% stimulation of transport of metabolizable and non-metabolizable neutral amino acids, of amino acid incorporation, and of inorganic sulfate incorporation. The effect of theophylline on amino acid transport was comparable to that of N 6,O 2′-dibutyryl adenosine 3′,5′-cyclic-phosphate but theophylline did not stimulate incorporation of amino acids or of sulfate. Cyclic 3′,5′-AMP (with or wihout theophylline), 5′-AMP, and potassium butyrate were without effect. Comparisons of the effects of N 6,O 2′-dibutyryl adenosine 3′,5′-cyclic-phosphate and of thyroid hormones on amino acid transport do not support the possibility that the stimulation by thyroid hormones is mediated by cyclic 3′-5′-AMP.