Prolactin (PRL) Function and Secretion Quiz

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Questions and Answers

What is the main role of prolactin in mammals?

Controlling water balance

Regulating salt balance

Enabling milk production (correct)

Influencing angiogenesis

When is prolactin secreted from the pituitary gland?

During fasting

During sleep

During exercise

In response to eating, mating, and nursing (correct)

In what manner does prolactin act as a growth factor?

Supporting muscle development

Controlling water and salt balance

Regulating blood clotting

Influencing hematopoiesis and angiogenesis (correct)

When was prolactin confirmed in humans?

Around 1970 (D) Signup and view all the answers

What is the source of prolactin in response to various events?

Pituitary gland (A) Signup and view all the answers

What is the function of prolactin in fish?

Controlling water balance (A) Signup and view all the answers

How does prolactin act in endocrine, autocrine, and paracrine manners?

Through the prolactin receptor and numerous cytokine receptors (D) Signup and view all the answers

In what manner does prolactin act as an important regulator of the immune system?

By acting as an anti-apoptotic factor (A) Signup and view all the answers

What is the main function of prolactin in pancreatic development?

Supporting cell differentiation (A) Signup and view all the answers

What is the primary influence of prolactin on metabolism?

Promoting fat storage (C) Signup and view all the answers

Which event triggers heavy secretion of prolactin?

Estrogen treatment (B) Signup and view all the answers

How does prolactin influence cell cycle-related functions?

By inhibiting cell death (apoptosis) (A) Signup and view all the answers

What stimulates extrapituitary prolactin production?

cAMP (B) Signup and view all the answers

Which hormone temporarily remains high after delivery to induce lactation?

Prolactin (D) Signup and view all the answers

During pregnancy, what increases prolactin levels by 10- to 20-fold?

Progesterone (A) Signup and view all the answers

What triggers the release of oxytocin from the posterior pituitary gland?

Sucking on the nipple (B) Signup and view all the answers

Which neuropeptide is a powerful prolactin-releasing factor in birds (turkeys)?

VIP (A) Signup and view all the answers

What hormone does not play a large role in raising prolactin levels in mice without a posterior pituitary?

Oxytocin (C) Signup and view all the answers

What do mice react to in terms of prolactin-releasing neuropeptides?

VIP and TRH (C) Signup and view all the answers

What is responsible for stimulating extrapituitary prolactin production?

cAMP–responsive element (B) Signup and view all the answers

What hormone upregulates prolactin synthesis in the endometrium but decreases it in myometrium and breast glandular tissue?

Progesterone (A) Signup and view all the answers

What does VIP act as in birds (turkeys)?

Powerful prolactin-releasing factor (C) Signup and view all the answers

What follows diurnal and ovulatory cycles?

Prolactin levels (A) Signup and view all the answers

What hormone inhibits the stimulatory effects of prolactin on milk production?

Estrogen (A) Signup and view all the answers

What is the principal control of thyrotropin-releasing hormone on prolactin release?

Inhibitory (B) Signup and view all the answers

Where are prolactin and its receptor expressed in the skin?

In hair follicles (C) Signup and view all the answers

What is the main function of prolactin in fish?

Osmoregulation (A) Signup and view all the answers

Which hormone inhibits prolactin production through Pit-1 transcription factor?

Dopamine (C) Signup and view all the answers

What is the effect of prolactin on mammary glands during puberty and pregnancy?

Stimulates growth (B) Signup and view all the answers

How does prolactin affect lipid synthesis in mammary and adipose cells?

Stimulates in both mammary and adipose cells (A) Signup and view all the answers

What effect does slightly elevated prolactin levels have on estrogen levels in humans?

No effect on estrogen levels (A) Signup and view all the answers

What is the effect of prolactin on luteinizing hormone-receptors in Leydig cells?

Activates the receptors (B) Signup and view all the answers

What triggers pituitary prolactin secretion?

Thyrotropin-releasing hormone (C) Signup and view all the answers

What is the function of prolactin in birds?

Affecting crop milk production (C) Signup and view all the answers

Where is prolactin produced in humans?

Breast (A) Signup and view all the answers

What is the effect of prolactin on myelin coatings on axons in the central nervous system?

Stimulates myelin formation (B) Signup and view all the answers

Study Notes

Pituitary prolactin secretion is regulated by neurons in the hypothalamus, specifically neurosecretory tuberoinfundibulum (TIDA) neurons of the arcuate nucleus.
TIDA neurons secrete dopamine (Prolactin Inhibitory Hormone) to act on lactotrophs' D2 receptors, inhibiting prolactin secretion.
Thyrotropin-releasing hormone stimulates prolactin release, but it is the only anterior pituitary hormone whose principal control is inhibitory.
Prolactin has multiple roles and forms. In humans, there are 14, 16, and 22 kDa variants, and it is closely related to somatolactin.
Prolactin stimulates mammary glands to produce milk and has effects on maternal behavior. It affects lipid synthesis differently in mammary and adipose cells and may affect sex hormone levels.
Prolactin inhibits gonadotropin-releasing hormone secretion but its exact mechanism is unknown.
In humans, prolactin enhances luteinizing hormone-receptors in Leydig cells, leading to testosterone secretion.
Prolactin stimulates oligodendrocyte precursor cells to form myelin coatings on axons in the central nervous system.
In fish, prolactin's primary function is osmoregulation but it also has reproductive functions.
Prolactin in fish controls the production of skin secretions and regulates hair growth and moulting in an autocrine fashion.
Prolactin receptor activation is essential for normal mammary gland development during puberty and pregnancy in mammals.
Prolactin is produced in multiple locations including the anterior pituitary, decidua, myometrium, breast, lymphocytes, leukocytes, and prostate.
Pituitary prolactin production is controlled by the Pit-1 transcription factor, which is inhibited by dopamine and stimulated by estrogens, neuropeptides, and growth factors.
Estrogens can suppress dopamine, and Thyrotropin-releasing hormone stimulates prolactin secretion.
Prolactin functions include lactation, maternal behavior, osmoregulation, and regulating sex hormones and hair growth.
In humans, slightly elevated prolactin levels can have variable effects on estrogen levels.
Prolactin has roles in reproduction, parental care, and pulmonary surfactant synthesis.
Prolactin and its receptor are expressed in the skin, specifically in hair follicles.
Prolactin has effects on feathering and crop milk production in birds.
Prolactin may play a role in the pleasurable perception of sad music in music psychology.
Prolactin can initiate pseudopregnancy in rodents.
Prolactin receptor activation is essential for normal mammary gland development and that adult virgin female prolactin receptor knockout mice have much smaller and less developed mammary glands.

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Description

Test your knowledge about the function and secretion of prolactin, a protein responsible for enabling mammals to produce milk and influencing over 300 processes in various vertebrates, including humans. Learn about its role in metabolism, immune system regulation, and more.