Introduction This study investigated the effects of intragastric administration of apelin-13 on the secretion of critical pancreatic hormones in a cohort of three-week-old Wistar rats. The research aimed to uncover apelin’s modulatory roles in endocrine interactions dictating metabolic homeostasis during early life. Material and Methods Rats were randomly assigned to control or experimental groups, receiving apelin-13 or saline for 14 days. The study population consisted of three-week-old Wistar rats of both sexes, weighing between 20 and 25 grams. Histological examination, analysis of variance and t-tests were employed to assess significant differences. Results Distinctive alterations in large islet morphology were observed, indicating a notable reduction in size. Additionally, an increase in alpha- and beta-cell density within specific islet sizes was noted, suggesting significant changes in cell populations. The study found a substantial increase in mitotic activity and a decrease in apoptosis in small and medium-sized islets post apelin-13 administration, indicating its potential role in regulating cell survival and proliferation. Conclusion The notable reduction in large islet size coupled with increased alpha and beta cell density implies a targeted impact of apelin-13 on pancreatic cell dynamics. Also, the observed increase in mitotic activity and decrease in apoptosis in small and medium-sized islets suggest its potential regulatory role in cell survival and proliferation within the pancreatic microenvironment.