subject: prolactin

Prolactin: One Hormone, Many Effects

Prolactin: One Hormone, Many Effects

Hormones are the body’s bike messengers, carrying important information from the endocrine glands (e.g., thyroid, pituitary, ovaries) to tissues throughout the body. Whereas GPS helps bike messengers find their intended recipients, hormones know they have found their target tissue when they are able to bind to hormonal receptors attached to a cell’s surface. Like a key fitting into a lock, hormones only bind to their specific receptor. Turning the key and opening the receptor’s lock allows the hormone to deliver its message to the cell, which responds by taking a particular action. The lactation hormone prolactin (PRL) has more than one target tissue, with prolactin receptors (PRLR) found in mammary glands, intestines, kidneys, ovaries, and even the heart. Mammary gland cells respond to PRL’s signal by secreting milk and initiating lactation, whereas cells of the intestines respond by increasing their absorption of calcium. How does the same hormonal signal result in the delivery of such different messages? Read More...

Prolactin Targets Intestines Too

Prolactin Targets Intestines Too

Prolactin (PRL) is a hormone that, as its name clearly indicates, PROmotes LACTation. Although it is best known for initiating milk production in the mammary glands, prolactin actually targets numerous other tissues throughout the body during lactation. One important target is the gut, where prolactin is believed to influence calcium absorption. A new study confirms this hypothesis, demonstrating that prolactin increases the ability of the intestines to absorb calcium and transfer it to the bloodstream. These important findings show that although PRL may have the important job of telling the mammary glands to make milk, it also plays a critical role in making sure that milk has all of the necessary ingredients. Read More...