Morphology and function of the rat oviduct: effects of thyroidectomy and thyroxine administration.

The effect of thyroidectomy and thyroxine administration on the morphology and function of the oviduct was studied in 40 albino rats. Chronic administration of 10 microg/100g for 60 days resulted in atrophy of the smooth muscle and mucosal folds. The thyroidectomized rats had reduced smooth muscle wall thickness, the epithelium reduced from columnar to cuboidal; and also flattening of mucosal folding. The contractile responses to oxytocin, acetylcholine and indeed the spontaneous contraction in the four thyroid states suggest a dependence of oviductal contraction on adequate plasma level of thyroid hormone in the vicinity of the contracting smooth muscle of the oviduct. The results suggest that thyroid hormone affects the morphology and function of the oviduct.