Effects of peripheral and central administration of GHRH on feeding in aging LOU rats

In aging LOU rats, a decreased protein intake is restored by GH administration. To study the contribution of GHRH to macronutrient selection, hGHRH NH(2) was administered sc. (1 mg/kg B.W./day/14 days) or icv. (4 and 40 pmol/rat) to 11-, 19-, 24- and 28-month-old rats. Sc. administration induced a decreased food and lipid intakes from 24 months of age and a transient stimulation of protein intake in 19-month-old and older low protein eaters (<10% protein/total intake). Icv. administration induced decreased food and lipid intakes in all age groups. These results suggest that GHRH may regulate feeding through pituitary and/or hypothalamic GHRH receptor mechanisms.