Development of psychophysiological motoric reactivity is influenced by peripubertal pharmacological inhibition of gonadotropin releasing hormone action – Results of an ovine model

• Published in: Psychoneuroendocrinology Vol. 37; no. 11; pp. 1876 - 1884
• Main Authors: Evans, Neil P, Robinson, Jane E, Erhard, Hans W, Ropstad, Erik, Fleming, Lynne M, Haraldsen, Ira Ronit Hebold
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.11.2012; Elsevier
• Subjects: Animal biology; Animals; Behavioral psychophysiology; Biological and medical sciences; Cortisol; Emotional reactivity; Emotions - drug effects; Endocrinology & Metabolism; Female; Fundamental and applied biological sciences. Psychology; GnRH; GnRH agonist; Gonadotropin-Releasing Hormone - antagonists & inhibitors; Gonadotropin-Releasing Hormone - physiology; Goserelin - pharmacology; Hormones and behavior; Hydrocortisone - blood; Life Sciences; Litter Size; Male; Motor Activity - drug effects; Motor Activity - physiology; Psychiatry; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology; Psychophysiological motoric reactivity; Puberty; Sex Factors; Sexual Maturation - drug effects; Sheep; Sheep - growth & development; Sheep - physiology; Stress; Vocalization, Animal - drug effects; Puberty; GnRH agonist; Emotional reactivity; Sheep; Cortisol; Psychophysiological motoric reactivity; GnRH; Stress; Affect affectivity; Agonist; Gonadotropin RH; Hydrocortisone; Glucocorticoid; Development; Inhibition; Hormone releasing factor; Ungulata; Psychophysiology; Corticosteroid; Steroid hormone; Antiinflammatory agent; Emotion emotionality; Hypothalamic hormone; Vertebrata; Mammalia; Reactivity; Animal; Adrenal hormone; Models; Artiodactyla; stress; cortisol; psychophysiological motoric reactivity; puberty; emotional reactivity; sheep
• DOI: 10.1016/j.psyneuen.2012.03.020
• ISSN: 0306-4530

Summary This study reports the effects of peripubertal GnRH receptor inactivation on development of psychophysiological motoric reactivity (PMR; sometimes also called emotional reactivity), plasma cortisol concentrations and the relationship between plasma cortisol and PMR in male and female sheep. The study formed part of a larger trial and utilised 46 same sex twins. One twin remained untreated (control) while the other received a subcutaneous GnRH agonist (GnRHa Goserelin-Acetate) implant every 4th week, beginning at 8 and 28 weeks of age, in males and females, respectively (different, due to sex specific age of puberty). PMR, a measure of an animals’ response to social isolation, was measured over a two minute period at 8, 28 and 48 weeks of age, using a three axis accelerometer. During the test period vocalisation rate was recorded. Cortisol was assayed in blood samples collected on a single day when animals were 40 weeks of age. PMR and vocalisation rate were significantly higher in females than males at all ages tested. At 28 weeks of age (20 weeks treatment) PMR was increased in treated males to the level seen in control females, by 48 weeks of age treated males’ PMR was significantly less than controls. In females, 20 weeks of GnRHa treatment (28–48 weeks of age) was not associated with differences in PMR. Cortisol concentrations were significantly higher in females than males but were not affected by treatment. Plasma cortisol concentrations were positively correlated with PMR; this relationship being driven by the treated animals in both sexes. The results demonstrate that PMR is sexually dimorphic and cortisol dependent in sheep from at least 8 weeks of age. Importantly, they also demonstrate that long-term treatment of males with a GnRH agonist results in changes in age-dependent development of PMR.