Sun14November1246PM 42

Which of the following is true of adrenocorticotropic hormone (ACTH)?

(Please select 1 option)

Is increased in the maternal plasma in pregnancy This is the correct answer

Production is governed by the pituitary Incorrect answer selected

Is not present in the placenta

Production is maximal about midnight

Secretion is inhibited by mineralocorticoids

Explanation

The production of ACTH is governed through the secretion of corticotropin-releasing hormone from the hypothalamic nuclei.

It governs cortisol secretion where cortisol is secreted maximally in the morning and concentrations are at a nadir at midnight.

ACTH can be expressed in numerous tissues besides the pituitary and including the placenta.

ACTH concentrations rise in stress, disease and in pregnancy.

Through negative feedback, glucocorticoids (not mineralocorticoids - aldosterone) switch off ACTH production.