Parathyroidectomy and Lactation in the Rat

Abstract

So far as we are aware, no accurate study of the effect of parathyroidectomy on lactation has yet been made, though Chandler1 noted that the young of parathyroidectomized rats were often smaller than normal, suggesting that lactation was impaired. In the rat, thyroidectomy entails removal of the two parathyroids, one of which is embedded in each lobe of the thyroid; but the marked decline in lactation which some workers2,3,4,5 have reported following thyroidectomy in the rat has usually been attributed to loss of the thyroid, since symptoms of tetany are generally not seen in rats thyroidectomized during lactation2,4,5. However, the results of Folley, Scott Watson and Amoroso5, who found that lactation could be partially maintained in thyroidectomized rats by parathyroid extract, suggested that the impairment of lactation following thyroidectomy may be, at any rate partially, due to loss of the parathyroids. If this were true it would seem possible that those workers6,7 who found that thyroidectomy had no effect on lactation used a strain of rat in which accessory parathyroids are the rule rather than the exception as is generally believed8.