Mammary Lobulo-Alveolar Growth Induced by Anterior Pituitary Hormones in Adreno-Ovariectomized and Adreno-Ovariectomized-Hypophysectomized Rats.

Abstract

1. Mature virgin female Car-worth rats of the CFN strain were adreno-ovariectomized and were then injected thrice daily for 10 days with saline, 2 mg bovine STH, 30 I.U. ovine prolactin, 20 mg bovine anterior pituitary powder, or with a combination of 1.33 mg bovine STH and 20 I.U. ovine prolactin. Treatment with STH and prolactin together or with anterior pituitary powder induced moderate to extensive mammary duct and lobulo-alveolar growth, while treatment with prolactin and STH alone induced mainly duct and end bud development. 2. Two groups of rats were hypophysectomized and 3 days later were adreno-ovariectomized. They were then injected thrice daily for 10 days with saline or with a combination of 1.33 mg STH and 20 I.U. prolactin for 10 days. The latter treatment induced extensive duct and moderate lobulo-alveolar growth. Completeness of ovariectomy, adrenalectomy and hypophysectomy was checked in all rats upon autopsy. Sixteen additional adreno-ovariectomized rats which were given tap water failed to survive more than 19 days. 3. It is concluded that under conditions of this experiment, full mammary duct and lobulo-alveolar growth was induced by combined treatment with bovine STH and ovine prolactin in the absence of ovaries and adrenals.