suppressive effect on pituitary TSH secretion (9). They also found that it was much more potent than T4 (10), although it was less abundant than T4 in the thyroid gland (11). Based on these findings Gross and Pitt-Rivers hypothesized that T3 was the active peripheral thyroid hormone and T4 was its precursor.
(Photo: Tom Tingle/The Republic) U.S. Sen. Jeff Flake may have a long two years ahead of him. Up for re-election in 2018, the first-term Arizona Republican is already under attack from the right and the left.
It wasn't easy dethroning Mitch McConnell as America's least favorite Senator, but Jeff Flake has done that in just three short months, a new poll out Monday reveals -- and his fall from rising-star grace is not quite the head-scratcher you might think.