Professor Dave Grattan's work centres around the pituitary hormone prolactin, “so, that's the control of prolactin secretion, and increasingly more focused around the actions of prolactin in the brain.” Prolactin is, as the name would suggest, known primarily for its role in lactation, however what Dave has noticed is that there are receptors for prolactin in a wide variety of areas within the brain. “Part of my goal over the past 10 years or so,” Dave says, “has been to say 'what are all these different functions of prolactin?'”
This question has, as you might expect, turned out to be quite consuming. With prolactin showing up as having a functional effect on everything from stress to metabolism it's become a gift that keeps on giving, a seemingly endless source of new questions and new puzzles. However, Dave and his team have started to catch on to a pattern; parenthood. Prolactin is present in male brains, as well as the brains of animals that can't lactate (e.g. zebra fish), which wouldn't make sense if it's key function was lactation. “There are a great many things that change in the brain during pregnancy, and prolactin has a finger in all of them,” Dave says, “and we suspect that similar changes are occurring in males also.” Instead of being a hormone with the singular function of milk production, prolactin may in fact be a hugely broad and impactful parental hormone.
By using various genetic knock-outs Dave's lab examines the individual pathways prolactin impacts: whether they be stress, metabolism, sleep, or some other function. What brings them all together is that key hormone. This flexibility has allowed for a secondary topic to branch out from Dave's focus on prolactin; the regulation of body weight and obesity. “Our interest in this started because during pregnancy food intake changes, appetite changes, and we've got maybe 15 years worth of work showing that the hormones that regulate body weight function are completely different in pregnancy,” Dave says, “so obviously our interest is: 'how is prolactin affecting those body weight hormones during pregnancy?'” The first step to answering that question is to understand how those hormones, insulin and leptin, function under normal conditions.
Focusing on a single hormone may sound restrictive, but with a hormone with as many functions as prolactin it's important to set limitations. With this strict focus Dave and his lab have managed to make a name for themselves in the international community, and can well and truly be considered experts in the field of prolactin research.