Final answer:
a. The hormone prolactin (PRL) is secreted by the anterior pituitary gland.
b. The target tissue for prolactin is the mammary glands (breasts).
c. Prolactin promotes lactation (milk production) in the mammary glands, especially in females.
d. It does not stimulate the thyroid gland or have a direct effect on the adrenal glands. Its primary role is related to reproduction and lactation.
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Step-by-step explanation:
Prolactin (PRL) is a hormone secreted by the anterior pituitary gland. It plays a significant role in lactation by stimulating the mammary glands to produce milk, especially after childbirth. Prolactin levels are modulated by prolactin-releasing hormone (PRH) and prolactin-inhibiting hormone (PIH), which is actually dopamine, both produced by the hypothalamus.
PRH encourages the release of prolactin, whereas PIH, or dopamine, inhibits it. The secretion of prolactin is part of a positive feedback loop, initiated by the suckling of a baby, which, through nerve impulses to the hypothalamus, leads to the increased release of prolactin and hence more milk production.
The target tissue for prolactin is the mammary glands, where it exerts its primary effect of promoting lactation. Moreover, the hormone supports the mobilization of maternal micronutrients essential for the milk's nutritional quality. Prolactin does not directly impact the thyroid or adrenal glands, as those are affected by other specific hormones produced by the anterior pituitary, such as thyroid-stimulating hormone (TSH) and adrenocorticotropic hormone (ACTH).