Obesity can cause a decrease in growth hormone (GH) secretion, but the reasons behind this are not fully understood. In this study, researchers looked at two hormones in the brain that regulate GH: GH-releasing factor (GRF) and somatostatin (SRIF). They found that obese rats had lower levels of GH pulses and GRF in the brain, leading to reduced GH secretion. Even when SRIF was blocked, GH levels did not increase. This suggests that the impaired GH secretion in obese rats is due to a lack of stimulation by GRF, rather than the action of SRIF.