Somatostatin regulation of fecundity and potential application to sturgeon roe production

Publications

Somatostatin signalling coordinates energy metabolism allocation to reproduction in zebrafish

Publication . Chen, Jie; Zhao, Wenting; Cao, Lei; Martins, Rute Sofia Tavares; Canario, Adelino

BackgroundEnergy allocation between growth and reproduction determines puberty onset and fertility. In mammals, peripheral hormones such as leptin, insulin and ghrelin signal metabolic information to the higher centres controlling gonadotrophin-releasing hormone neurone activity. However, these observations could not be confirmed in lower vertebrates, suggesting that other factors may mediate the energetic trade-off between growth and reproduction. A bioinformatic and experimental study suggested co-regulation of the circadian clock, reproductive axis and growth-regulating genes in zebrafish. While loss-of-function of most of the identified co-regulated genes had no effect or only had mild effects on reproduction, no such information existed about the co-regulated somatostatin, well-known for its actions on growth and metabolism.ResultsWe show that somatostatin signalling is pivotal in regulating fecundity and metabolism. Knock-out of zebrafish somatostatin 1.1 (sst1.1) and somatostatin 1.2 (sst1.2) caused a 20-30% increase in embryonic primordial germ cells, and sst1.2-/- adults laid 40% more eggs than their wild-type siblings. The sst1.1-/- and sst1.2-/- mutants had divergent metabolic phenotypes: the former had 25% more pancreatic alpha-cells, were hyperglycaemic and glucose intolerant, and had increased adipocyte mass; the latter had 25% more pancreatic beta-cells, improved glucose clearance and reduced adipocyte mass.ConclusionsWe conclude that somatostatin signalling regulates energy metabolism and fecundity through anti-proliferative and modulatory actions on primordial germ cells, pancreatic insulin and glucagon cells and the hypothalamus. The ancient origin of the somatostatin system suggests it could act as a switch linking metabolism and reproduction across vertebrates. The results raise the possibility of applications in human and animal fertility.

2024-07-29Journal article

Open Access

Metabolic changes in response to food intake in somatostatin 1.1 deficient zebrafish

Publication . Chen, Jie; Yuan, Huiming; Gao, Jing; Liu, Lu; Canario, Adelino

Somatostatin is a multifunctional hormone with several genes in teleost fishes. A zebrafish CRISPR/Cas9 knockout of the somatostatin 1.1 ( sst1.1 ) with persistent hyperglycaemia and hyperlipidaemia displayed reduced fecundity when fed brine shrimp ad libitum. Here, we investigated the effect of feeding brine shrimp one to three times a day on fecundity and liver transcriptomics of the sst1.1 mutant compared to their wild-type siblings to unravel molecular pathways associated with the phenotype. We find that the sst1.1 deficient zebrafish had high mortality when fed at the highest rate and that in both genotypes, growth and fecundity were proportional to food intake. Although glucose and cholesterol decreased substantially at the lowest level of feeding, they were still higher in the mutant than in the wild-type zebrafish. Furthermore, sst1.1 deficiency had a small but significant effect on the hepatic expression of protein, carbohydrate, and fatty acid biosynthesis genes, contributing to the mutant's diabetic phenotype.

2024-12Journal article

Open Access