Ovariectomy-induced tubulin polymerization in pregnant rat mammary gland

The pool of polymerized (microtubular) tubulin in the mammary glands of pregnant rats, ovariectomized (OVX) at 18 days, increased approximately threefold between 18 and 24 hr following ovariectomy, as determined by 3H-colchicine binding assay, while that of the sham-operated animals showed no change. Total tubulin content did not change in either OVX or sham animals. The polymerized pool and the total tubulin in 9-day lactating mammary glands were significantly greater than in the mammary glands of OVX or sham rats.