Blockade of the stress-induced decrease in blood GH by anti-somatostatin serum in rats.

Area of Science:

• Endocrinology
• Neuroscience
• Physiology

Background:

• Somatostatin is a hormone with known inhibitory effects on growth hormone (GH) release.
• The precise role of somatostatin in regulating GH secretion, especially under stressful conditions, requires further elucidation.

Purpose of the Study:

• To investigate the physiological role of somatostatin in the mechanism of GH release in rats.
• To determine the effect of passive immunization with somatostatin on basal and post-stress serum GH levels.

Main Methods:

• Adult male rats were passively immunized against somatostatin using sheep antiserum or normal sheep serum (NSS).
• Serum GH levels were measured basally and following stressful stimuli (ether exposure, electroshock).
• Statistical analysis was performed to compare GH levels between antiserum-treated and control groups.

Main Results:

• Passive immunization with somatostatin antiserum led to increased basal serum GH levels, though not statistically significant due to variation.
• Post-stress serum GH levels were significantly higher in rats pre-treated with somatostatin antiserum compared to NSS-treated or non-treated controls.
• Stress-induced GH secretion was significantly blunted in rats treated with NSS or untreated.

Conclusions:

• The stress-induced decrease in GH secretion in rats is, at least partly, mediated by increased release of hypothalamic somatostatin or related inhibitory hormones.
• The persistent variation in serum GH levels after somatostatin neutralization suggests that other regulators, such as GH-releasing hormone, also play a role in controlling GH secretion.