Feeding behavior during long-term hexarelin administration in young and old rats

Area of Science:

• Endocrinology
• Neuroscience
• Gastroenterology

Background:

• Ghrelin is the sole known circulating appetite-stimulating hormone and the natural ligand for the GH-secretagogues receptor-1a (GHS-R1a).
• Synthetic GH secretagogues (GHS) can stimulate GH secretion and feeding, with research focusing on their long-term effects on GH release.
• Limited data exist on the long-term extraendocrine effects of GHS, especially concerning appetite stimulation in aged animal models.

Purpose of the Study:

• To determine the minimal dose of hexarelin that maximally stimulates food intake in young and old rats.
• To investigate the chronic effects of daily hexarelin administration on food intake and body weight in young and old rats over an 8-week period.

Main Methods:

• A dose-response study (80-320 microg/kg, s.c.) was conducted to identify the optimal hexarelin dose for stimulating food intake.
• Young (3-month-old) and old (24-month-old) male rats received daily subcutaneous injections of hexarelin (80 microg/kg) for 8 weeks.
• Food consumption and body weight gain were monitored throughout the treatment period.

Main Results:

• Hexarelin at 80 microg/kg reproducibly induced maximal stimulation of food consumption in both young and old rats.
• Chronic daily administration of hexarelin (80 microg/kg) sustained a significant orexigenic (appetite-stimulating) effect throughout the 8-week treatment in both age groups.
• Hexarelin treatment did not significantly alter body weight gain in either young or old rats.

Conclusions:

• Hexarelin possesses a long-lasting appetite-stimulating activity.
• Hexarelin may hold therapeutic potential for conditions associated with reduced food intake.