Renin-angiotensin system in the anterior pituitary of the rat.

In rats, angiotensin II appears to be synthesized in the anterior pituitary gland and stored in gonadotropes in the same granules as the beta-subunit of luteinizing hormone (LH). The gonadotropes also contain renin-like and angiotensin-converting enzyme-like immunoreactivity, but angiotensinogen-like immunoreactivity is found in a separate population of cells and does not colocalize with any of the known anterior pituitary hormones. This suggests that angiotensinogen shuttles to the gonadotropes in a paracrine fashion. There are angiotensin II receptors on lactotropes and corticotropes, but no definite function has been established for pituitary angiotensin II in the regulation of prolactin and adrenocorticotropic hormone.