Linking Ghrelin Elevation to Reproductive Dysfunction: Insights from Feed-Restricted Male Rats

Ghrelin, a peptide hormone consisting of 28 amino acids and primarily produced in the stomach, is crucial for stimulating appetite and maintaining energy balance. Beyond its role in hunger and metabolism, ghrelin also influences the hypothalamic-pituitary-gonadal (HPG) axis, impacting reproductive hormones secretion. During starvation, ghrelin levels increase as part of the body's energy conservation response. The study explored the impact of feed restriction on ghrelin levels and the expression of the ghrelin gene in the gastric fundus, hypothalamus, and testes, as well as their association with reproductive function in adult male rats. Thirty adult male Swiss albino rats were assigned to three groups: a control group (ad libitum feeding), a 30% feed restriction group, and a 60% feed restriction group, over two months. An additional ten adult female rats were included to assess changes in male sexual behavior. Feed restriction resulted in a marked increase in ghrelin levels and its gene expression in the examined tissues, with the most pronounced elevation observed in the 60% feed restricted group. Elevated ghrelin disrupted the HPG axis, leading to reduced levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), and testosterone, while prolactin levels increased. These hormonal changes negatively impacted fertility, libido, semen quality, and overall sexual function. Additionally, feed restrictions caused histopathological alterations in the stomach and testes, along with reductions in both testicular and body weight. These findings suggest that increased ghrelin hormone, in response to energy deficiency, may inhibit the male reproductive axis, linking energy balance and reproductive function in male rats.