Maternal hypothyroidism-milk ejections: What is the link?

What is it about?

The normal activity for the maternal hypothalamic-pituitary-thyroid axis (HPTA) is dynamic for the developing fetuses and neonates, especially the function and activity of mammary gland. Thyroid hormones (THs) stimulate the signal transducer activator of transcription 5 (STAT5) proteins and ovarian hormone receptors-induced the differentiation of the mammary epithelial cell by their nuclear receptors (TRs). More interestingly, THs, prolactin (PRL), glucocorticoids and ovarian hormones (estrogen and progesterone) can regulate the involution switch process in the mammary epithelial cell by activating several signaling pathways such as mitogen-activated protein kinase (MAPK) and JAK/STAT. On the other hand, the defect in the lactation mechanism due to hypothyroidism can be illustrated as the following: (1) reduced the quality of milk nutrition quality; (2) dysfunction in the milk ejection due to the reduction in the response of oxytocin (OXT); (3) disorders in the accumulation of milk in the alveoli; (4) decreased the growth rate of the litter/pups and increased the litter mortality; (5) milk stasis and mammary involution; and (6) disturbance in the signaling of PRL and elevation in the signaling of PRL inhibitors including LIF and STAT3. Thus, the maternal hypothyroidism may directly or indirectly increase the risk of the premature mammary involution and destruction of the mammary tissue. This state may suppress the normal development. Thus, we can avoid these abnormalities if we controlling the activities of the maternal PRL, T3, T4, growth hormone (GH), and thyroid-stimulating hormone (TSH) during the gestation and lactation. Additional experiments are needed to identify the associations between the maternal hypothyroidism, lactation disorders and mammary carcinogenesis.

Featured Image

Why is it important?

the maternal hypothyroidism may directly or indirectly increase the risk of the premature mammary involution and destruction of the mammary tissue. This state may suppress the normal development.

Perspectives