Ovarian, Hypophyseal and Hypothalamic Hormones Coordinate Mammary Gland Remodeling in Adult Lagostomus maximus: a Rodent that Shows Pseudo-Ovulation at Mid-Gestation

Abstract

Adult female mammary glands go through extensive tissue remodeling during pregnancy, lactation and after the weaning of the neonates. Here we characterize mammary gland morphology of adult females of Lagostomus maximus, a hystricomorph rodent with a pseudo-ovulatory event at mid-gestation, and describe how the glandular tissue changes its architecture in response to variations of the hormonal environment. At mid-gestation, pseudo-ovulation is seen as an essential event increasing the number of secondary corpora lutea and thus rising the circulating levels of progesterone that help to maintain pregnancy to term. As a side effect, mammary gland development is favored early during the long-lasting pregnancy of L. maximus, preparing females for the nutritional need of fully developed pups in this k-strategist species.

Prolactin Is a Strong Candidate for the Regulation of Luteal Steroidogenesis in Vizcachas (Lagostomus maximus)

“…However, it must be considered that mammary glands are the primary target of PRL. In fact, pituitary PRL expression determined in this study is in agreement with the documented increased expression of PRLR in mammary glands of vizcachas throughout gestation and this is tightly related to the mammary gland preparation for the eventual nurturing of the forthcoming offspring [ 29 , 38 , 56 ].…”

“…Nonpregnant females were captured in mid-September after the end of the reproductive season. Lactating female group (LCT) was established by selecting those nonpregnant animals whose mammary glands exhibited the histological features already described for this period [ 29 , 38 ] ( Table 1 ).…”