Which of the following statement(s) is/are true concerning the effect of various hormones on breast physiology?

b. Mammary ductal dilatation and differentiation of alveolar epithelial cells and secretory cells are the result of rising progesterone levels

d. Milk production and secretion after childbirth are maintained by ongoing secretion of prolactin by the anterior pituitary gland

Breast growth, development, and function are orchestrated by a variety of hormones and growth factors. Estrogen plays a central role in breast development, growth, and differentiation. Lipid-soluble estrogens gain entry to the normal and malignant breast cell by diffusing to the cell membrane. Once within the cell, estrogens bind with the estrogen receptor. Both normal and malignant breast cells contain estrogen receptors, but the low levels of receptors in normal breast tissue and in some breast cancers result in their testing negative in clinical assays. Cyclic changes associated with the menstrual cycle have a profound influence on breast morphology and physiology. During the period of relative quiescence, increasing Graafian follicle secretion of estrogen stimulates breast epithelial proliferation. As the luteal phase of the cycle is entered, progesterone levels rise. Mammary ductal dilatation and differentiation of alveolus epithelial cells into secretory cells result. At the onset of menstruation, the rapid decline of circulating sex-hormone levels leads to breast involution and the cycle begins anew. During pregnancy, marked ductular, lobular, and alveolar growth occur under the influence of estrogen, progesterone, placental lactogen, prolactin, and chorionic gonadotropin. These changes prepare the breasts for milk production at parturition. Early in the first trimester, ductal sprouting and lobular formation proceed under estrogenic influence. During the second trimester, lobular events predominate under the influence of progestins. Abrupt withdrawal of placental lactogen and sex-hormones that occurs with delivery, leaves the breast predominately under the influence of pituitary-derived prolactin. Milk production and secretion are maintained during lactation by ongoing secretion of prolactin by the anterior pituitary.