Q.Which of the following hormone is not secreted under the influence of pituitary gland?
a. thyroxine
b. insulin
c. oestrogen
d. glucocorticoids

The hypothalamus controls the anterior pituitary through the hypophyseal portal system, a set of portal blood vessels carrying hypothalamic releasing/inhibiting hormones directly to the anterior pituitary — option (d).

The hypothalamus regulates the pituitary gland in two different ways for its two lobes:

• For the posterior pituitary (neurohypophysis), the connection is neural/axonal — hypothalamic neurons' axons extend directly into the posterior pituitary and release hormones like oxytocin and ADH from their nerve endings there.
• For the anterior pituitary (adenohypophysis), there is no direct nervous connection. Instead, a specialised network of blood vessels called the hypophyseal portal system carries hypothalamic releasing hormones (e.g., TRH, GnRH, CRH) and inhibiting hormones from the hypothalamus directly into the capillary bed of the anterior pituitary, where they stimulate or inhibit the secretion of anterior pituitary hormones.

Options (a) and (b), which mention dendrites/axons of the neurohypophysis, actually describe the route to the POSTERIOR pituitary, not the anterior lobe asked about here. Option (c) is not a real anatomical connection between the hypothalamus and pituitary.