ABSTRACT
Although the TSH receptor and Galpha(s), which activate the cAMP cascade in the thyroid gland have been much studied, nothing is known about the adenylyl cyclase (AC) isoforms which are actually involved in this pathway. To characterize the cAMP generation in the dog and human thyroid gland, resulting from the presence of distinct adenylyl cyclase families, the responses to various agents (Ca2+, calmodulin (CaM), phorbol esters (TPA) and thapsigargin (Tg)) were studied. These experiments suggest a role of at least two families of cyclases: cyclases negatively modulated by Ca2+ (ACV or ACVI) and cyclases positively modulated by PKC (ACII, ACIII or ACVII). To further analyze by other experimental procedures the expression pattern of the cyclase isoforms in the thyroid gland, Northern blotting, Western blotting and RT-PCR experiments were performed. The results clearly suggest that in both species, three different adenylyl cyclases ACIII, ACVI and ACIX are mainly expressed in thyrocytes.
Subject(s)
Adenylyl Cyclases/metabolism , Gene Expression , Thyroid Gland/enzymology , Adenylyl Cyclases/analysis , Adenylyl Cyclases/genetics , Animals , Cell Membrane/metabolism , Cells, Cultured , Cyclic AMP/metabolism , Dogs , Humans , Isoenzymes/genetics , Isoenzymes/metabolism , Protein Isoforms/analysis , Protein Isoforms/genetics , Protein Isoforms/metabolism , RNA/analysis , RNA/metabolism , Thyroid Gland/cytology , Thyroid Gland/metabolism , Tissue DistributionABSTRACT
The weights and heights of 1,880 male military parachutists were recorded, and landing injury rates were calculated according to the weights and heights of the jumpers. Only the weight significantly influenced the injury rate. The set of data (weight, injury rate) are best fitted with a parabola of the form: y = 43.14 - 1.22x + 0.01x2. The concept of the maximal operating weight of a parachute is discussed with its implications for medical standards and for jumps with extra equipment.