DailyMail reports that a team of Canadian researchers have discovered a new sex hormone in zebrafish. They say this discovery could lead to developing better fertility treatment options for humans.
The researchers successfully restored partial sexual function in genetically mutated zebrafish with a single injection. In their trial, the jab was able to enhance further the ability of the female fish to ovulate and lay her eggs.
The fish possessed about 70% genes similar to humans, which makes it the perfect lab models. According to researchers, the key to the process is a small-like-molecule produced by the fish. Moreover, this molecule is found in other animals and humans as well.
According to Vance Trudeau, the senior author of the study, they mutated two related genes and analyzed their effects on the zebrafish's sexual function. Trudeau is a Professor of Neuroendocrinology at the University of Ottawa, Canada.
Additionally, he said that they used genetically modified fish to search for other factors that could improve sexual function. The researchers looked for clues leaning toward either increased spawning in cultured fish species or helping with the search for new infertility treatments for humans.
The findings of the research were published in Proceedings of the National Academy of Sciences.
Uncovering New Sex Hormones
Professor Trudeau and his co-author Kim Mitchell had discovered new functions that facilitate how males and females interact while mating when they initially started studying the effects of gene mutations in zebrafish.
Using gene technology developed at the Chinese Academy of Sciences, in Wuhan, China, the researchers were able to mutate two related genes under the name secretogranin-2. It encodes the protein with the same name.
Trudeau said that the first step of their experiments was to perform the gene editing to reduce the zebrafish's sexual behaviour. Furthermore, they changed the secretogranin-2 genes through specific mutations. The authors of the study found that it significantly affected the ability of females and males to breed.
According to Trudeau, it severely reduced their sexual behaviour. At first, the fish appeared normal. However, when both sexes were put together, they completely ignored each other. He explained how normally the male and female fish would engage in a 'courtship ritual' in which the male would chase the female.
Generally after the courtship, the female dispenses her eggs to the water, and the male fertilizes them. However, in a sample of gene-edited zebrafish couples used in the study, the researchers found only one in ten were able to spawn.
The experiments showed that the fish carrying the delivered mutations were capable of producing sperm and eggs, but were dreadful at mating. According to Trudeau, it was the first evidence that showed the mutation of genes leading to the disruption of sexual behaviour in animals.
Future Fertility Treatments
For the experiment's second stage, the researchers used a fragment of secretogranin-2 in an attempt to reverse the seeming incapacity to mate. The team was able to partially restore sexual function by a single injection of the secretoneurin peptide into the fish's body.
The researchers revealed new genes that can determine reproduction. Furthermore, the secretoneurin peptide itself has been classified as a new hormone with possible connotations for future fertility research.
According to Trudeau, the large secretogranin-2 genes could produce several other hormone-like peptides with functions still left to be discovered. He added that it would be exciting to explore the subject in future projects further.
