In which of the following forms the Anti diuretic hormone (ADH) is circulated in plasma?
A. Bound to neurophysin – IB. Bound to neurophysin – II
C. Bound to plasma albumin
D. Free from
The Answer is. B
· The hormones of
the post – pituitary gland (ADH and oxytocin) are synthesized in the cell
bodies of magnocellular neurons in the supraoptic and paraventricular nuclei
· Vasopressin and
oxytocin each have a characteristic neurophysin in the granules in the neurons
that secrete them. neurophysin II in case of vasopressin and neurophysin I in
case of oxytocin.
· ADH secretion is
enhanced by angiotensin II, prostaglandin, histamine, neuropeptide Y and Ach
and is inhibited by GABA and ANP.
· ADH responsive
water channel is collecting ducts of kidney is aquaporin – 2
