The effect of ketamine/xylazine and carbon dioxide on plasma luteinizing hormone releasing hormone and testosterone concentrations in the male Norway rat

Abstract

SummaryThe effect of a commonly used anaesthetic, ketamine/xylazine and/or carbon dioxide (CO 2 ) on plasma luteinizing hormone releasing hormone (LHRH) and testosterone concentrations was determined in male Sprague-Dawley rats. These values were compared with values obtained from pre-anaesthetic control samples. Ketamine/xylazine treatment did not significantly affect testosterone concentrations. In contrast, LHRH started to decrease one hour after ketamine/xylazine administration and continued to significantly decrease after 24 h. In addition, in the CO 2 euthanasia-only group, LHRH concentrations were also significantly decreased. These results suggest that ketamine/xylazine anaesthesia followed by CO 2 euthanasia 24 h later is exerting a significant effect on LHRH concentrations 24 h after anaesthetizing, while only having a slight effect on testosterone, and that CO 2 is exerting an immediate significant effect on LHRH. In conclusion, LHRH analysis should be avoided after ketamine/xylazine anaesthesia and CO 2 euthanasia.

Ketamine attenuates cytochrome p450 aromatase gene expression and estradiol‐17β levels in zebrafish early life stages

“…Anesthetics have complex neuroendocrine effects and ketamine is known to block spontaneous GnRH (gonadotropin‐releasing horomone) release and to decrease peripheral LH levels in adult rats (Cohen et al ., ; Emanuele et al ., ; Matzen et al ., ; Sherwood et al ., ). However, in male Sprague–Dawley rats, ketamine treatment increased testosterone concentrations, but decreased LHRH (luteinizing hormone‐releasing hormone) after 1 of administration and continued to significantly decrease after 24 h (Gould, ). In the present study, an effort to investigate whether ketamine influenced E2 concentration and CYP aromatase expression in zebrafish embryos was based on the reports that ketamine regulates a number of CYPs in mammals (Chen and Chen, ) and alters the serum concentrations of several hormones, such as progesterone, testosterone and E2 in cyclic rats (Lee et al ., ).…”

“…Ketamine‐treated embryos showed an increase in testosterone level, which is in agreement with data reported in male boars (Estienne and Barb ), male collared peccary ( Tayassu tajacu ) (Hellgren et al ., ) and female Norway rats (Gould, ). In contrast, ketamine has been shown to cause a reduction in plasma testosterone levels in men (Oyama et al ., ), domestic tom cats (Johnstone and Bancroft, ) and cyclic female Sprague–Dawley rats (Lee et al ., ).…”

Plasma Testosterone and Androstenedione Levels Follow the Same Sex-Specific Patterns in the Two Pan Species

“…Another aspect that may have affected testosterone levels in our study subjects is the fact that samples were drawn while individuals were sedated; in some species some types of sedation and anesthesia were associated with lower (e.g., [ 65 ]) or increased (e.g., [ 66 ]) testosterone level measurements during and after sedation. In other studies, no relation between testosterone levels and anesthesia/sedation drugs (ketamine/xylazine) were found (e.g., [ 67 , 68 ]). To our knowledge, the effects of ketamine/xylazine, which are commonly used by zoo veterinarians for great apes, or any other anesthesia drug (such as barbiturates) have not yet been investigated in bonobos or chimpanzees.…”

Factors That Can Influence Animal Research

“…Reported anesthetic-induced alterations include both increased and decreased cortisol and catecholamine secretion; increased concentrations of serum ACTH, growth hormone, thyroxine, antidiuretic hormone, and renin; and decreased secretion of luteinizing hormone, aldosterone, and testosterone (Dispersyn et al, 2009;Gould, 2008;Oyama, 1973;Pettinger et al, 1975;Xu et al, 2012;Zaretsky et al, 2010). Reported anesthetic-induced alterations include both increased and decreased cortisol and catecholamine secretion; increased concentrations of serum ACTH, growth hormone, thyroxine, antidiuretic hormone, and renin; and decreased secretion of luteinizing hormone, aldosterone, and testosterone (Dispersyn et al, 2009;Gould, 2008;Oyama, 1973;Pettinger et al, 1975;Xu et al, 2012;Zaretsky et al, 2010).…”