title: Absence of response of chick embryonic limb to the growth stimulatory effect of parathyroid hormone in vitro after exposure to 6-aminonicotinamide in ovo.
abstract: The biochemical effect of a nicotinamide analogue, 6-aminonicotinamide (6-AN), on developing chick embryonic femur was studied. Growth of femur from 9-day-old embryos that had been exposed to 6-AN for 5 days in ovo was not stimulated by PTH in an in vitro culture system. PTH caused a much smaller increase in the cyclic-AMP content in 6-AN-treated femur than in control femur. However, dibutyryl cyclic-AMP stimulated growth of 6-AN-treated femur. A defect in response of 6-AN-treated femur to the growth stimulating action of PTH may explain the production of micromelia by 6-AN.
mesh_terms: D015120:6-Aminonicotinamide / Q000494:pharmacology*; D000818:Animals; D003994:Bucladesine / Q000494:pharmacology; D002642:Chick Embryo; D046508:Culture Techniques; D000242:Cyclic AMP / Q000378:metabolism; D005121:Extremities / Q000187:drug effects / Q000196:embryology* / Q000378:metabolism; D007700:Kinetics; D009536:Niacinamide / Q000031:analogs & derivatives*; D010281:Parathyroid Hormone / Q000494:pharmacology*
chemical_list: D010281:Parathyroid Hormone; D009536:Niacinamide; D015120:6-Aminonicotinamide; D003994:Bucladesine; D000242:Cyclic AMP