New insights into breast-feeding hormone

Jan 28, 2010

(PhysOrg.com) -- A mechanism for regulating the hormone prolactin has newly been revealed by scientists at Karolinska Institutet, Sweden. The results are to be published in the scientific journal Neuron, and may be significant for conditions and functions such as breast-feeding, sexual libido, and metabolism.

The hormone, prolactin, is released from the pituitary gland in the brain and is the signal that triggers production during nursing. The reason that women normally do not produce milk - and men never do - is that the release of prolactin is normally strongly inhibited by the signal substance dopamine. This is secreted by cells known as "TIDA" in the in the brain.

A research group at Karolinska Institutet has now for the first time investigated the of the dopamine-producing TIDA cells, in order to understand in more depth the regulation of prolactin. The study has shown that the cells normally display an extremely rhythmical activity, with discharges every 20 seconds. The scientists believe that this rhythmical behaviour lies behind the ability of the TIDA cells to function as a strong inhibitor of prolactin release.

"It is known that rhythmical signalling makes it possible for to release large quantities of signal substances", says Christian Broberger, who has led the study.

The study has also shown that TRH (thyrotropin-releasing hormone), a signal substance that is known to stimulate the release of prolactin, can interrupt the rhythmical signalling pattern of TIDA cells.

Prolactin plays important roles in reproduction and fertility, one of which is reduction of sexual libido. Prolactin is released during orgasm. It is believed that prolactin is significant for , since patients with elevated levels of prolactin can become overweight. Levels of prolactin often rise in patients who are treated with dopamine inhibitors for psychotic disorders, and these patients often experience loss of libido and sometimes the production of breast milk as undesired effects.

"Our results increase the possibility of being able to treat problems of prolactin release, not least the undesired effects that arise when using drugs that inhibit dopamine", says Christian Broberger.

Explore further: 'Tickling' your ear could be good for your heart

More information: David J. Lyons, Emilia Horjales-Araujo och Christian Broberger, Synchronized Network Oscillations in Rat Tuberoinfundibular Dopamine Neurons: Switch to Tonic Discharge by Thyrotropin-Releasing Hormone, Neuron 27 Jan 2010

add to favorites email to friend print save as pdf

Related Stories

Postpartum anxiety delays puberty in offspring

Jun 10, 2009

Hormonal changes early in pregnancy cause maternal postpartum anxiety and behavior changes that can lead to a delayed onset of puberty in both birth and adoptive daughters, according to a new study conducted in mice.

Genetic links to impaired social behavior in autism

May 13, 2008

Individuals with autism spectrum disorders (ASD) show profound deficits in social interactions and communications, and display repetitive behaviors and abnormal responses to sensory experiences. One aspect of an autistic ...

New dopamine brain target discovered

Jan 23, 2007

A team of Canadian researchers, lead by Dr. Susan George and Dr. Brian O'Dowd at the Centre for Addiction and Mental health (CAMH), discovered a distinct dopamine signalling complex in the brain. Composed of two different ...

Recommended for you

Celebrities in 'Ice Bucket Challenge' to fight disease

8 hours ago

Steven Spielberg, Justin Bieber and Bill Gates are among many celebrities pouring buckets of ice water over their heads and donating to fight Lou Gehrig's disease, in a fundraising effort that has gone viral.

Study helps explain why elderly have trouble sleeping

9 hours ago

As people grow older, they often have difficulty falling asleep and staying asleep, and tend to awaken too early in the morning. In individuals with Alzheimer's disease, this common and troubling symptom ...

Targeted brain training may help you multitask better

10 hours ago

The area of the brain involved in multitasking and ways to train it have been identified by a research team at the IUGM Institut universitaire de gériatrie de Montréal and the University of Montreal.

User comments : 0