Stem cells discovered for the first time in the pituitary

5 May, 2008

New developments are always being announced in research in the field of stem cells. The latest is the discovery of stem cells in pituitary glands of mice.

A team of scientists has discovered stem cells that allow the pituitary glands to grow even after birth in mice. This is for the first time that such a stem cell has been identified. A group of scientists at Cold Spring Harbor Laboratory have found that these stem cells are different from the majority of adult stem cells that trigger the initial growth of this important organ. The study also suggests a new model for diagnose traumatic stress or normal life changes like pregnancy in adolescents and adults.

Grigori Enikolopov, an associate professor at Cold Spring Harbor Laboratory (CSHL) had earlier found out that a gene called Nestin was active in neural stem cells. The team had genetically engineered mice so that the same conditions that activate Nestin in a particular cell also make it glow green under ultraviolet light. After that there have been many attempts to use these special mice to help find adult stem cells in hair follicles, liver, muscle, and other tissues. The pituitary gland in humans is about the size of a pea and sits at the base of the brain, where it secretes hormones that regulate various processes throughout the body. However, in
mice, the gland develops in the embryo, but then has a second growth spurt.

The new team has used the Nestin-tracking mice to identify candidate cells in the anterior pituitary, the section of the organ that secretes hormones. Then they had used other techniques to show that these are true stem cells.

The researchers showed that adult stem cells in the pituitary did not help construct the embryonic organ. The research indicates that the adult mouse pituitary includes two similar, but not identical, types of hormone-producing cells. Some of these cells are growing in the developing embryo and some of them appeared later. It is hypothesised that presence of two sets of cells will help in knowing the the organ response differently to changing body conditions.

Despite some opposition in the US, stem cell research is proceeding apace, and new deveopments are always being announced. But there surely is a long way to go.