Pituitary and gonadal response to exogenous LH-releasing hormone in the male domestic cat.
ABSTRACT To determine the influence of exogenous LH-releasing hormone (LHRH) on serum LH and testosterone, ten adult male domestic cats received three treatments on a rotating schedule at 10-day intervals as follows: (I) 0.1 ml saline i.m. (control); (II) 10 micrograms LHRH i.m., single injection; (III) 10 micrograms LHRH i.m., two injections given at a 2-h interval. Serial blood samples collected over a 360-min interval were analysed by radio-immunoassay for LH and testosterone. Although baseline serum LH values in saline-treated animals (treatment I) varied markedly among individual cats (2.2-29.2 micrograms/l), there was no evidence of pulsatile LH release or alterations in testosterone over time within individual males. In treatment II, the single injection of LHRH induced a rapid rise in mean serum LH within 30 min in all cats (mean peak, 88.2 +/- 9.8 micrograms/l), which returned to baseline by 120 min after LHRH. Mean testosterone increased within 30 min in this group (from 6.03 +/- 2.18 to 18.55 +/- 3.36 nmol/l), peaked at the 60-min collection (19.76 +/- 2.77 nmol/l) and returned to baseline by the 150-min sample. After treatment III, serum LH peaked at 131.6 +/- 13.6 micrograms/l within 30 min of the initial LHRH injection. A second injection of LHRH produced another LH surge within 30 min, but in all cats this second response was of a lower magnitude (mean peak, 69.0 +/- 14.5 micrograms/l) and shorter duration (P less than 0.05). The second LHRH injection sustained peripheral testosterone levels for approximately 1 additional h.(ABSTRACT TRUNCATED AT 250 WORDS)
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ABSTRACT: Sixteen domestic cats were used to investigate the pituitary-adrenal, pituitary-gonadal and behavioral consequences of an unpredictable handling and husbandry routine. After a 10-day baseline period of standard laboratory procedures, eight cats (‘stressed cats’, STR) were subjected to a 21-day period of altered caretaking characterized by irregular feeding and cleaning times, absence of talking and petting by humans, and daily unpredictable manipulations. Eight control cats (CON group) were maintained for 21 days on the standard caretaking schedule. Behavior was recorded on time-lapse video 24 h day−1, urine was collected daily for cortisol analyses, and hormone stimulation tests with synthetic adrenocorticotropic hormone (ACTH) and luteinizing hormone-releasing hormone (LHRH) were conducted before and after the 3-week treatment period. Results indicate that the STR cats were chronically stressed by the altered caretaking routine. Urinary cortisol concentrations were consistently elevated throughout the 3-week period, adrenal sensitivity to ACTH was enhanced and pituitary sensitivity to LHRH was reduced. Active exploratory and play behavior was suppressed, and STR cats spent more time awake/alert and attempting to hide. Hiding was negatively correlated with cortisol concentration and, therefore, may be an important behavior for coping with uncontrollable and unpredictable captive environments. These results indicate that qualitatively poor caretaking is a potent psychological stressor for confined cats that may eventually compromise reproduction through behavioral or physiological mechanisms. To promote well-being, caged cats should be provided with appropriate places for concealment.Applied Animal Behaviour Science 11/1993; 38(2):143–158. · 1.63 Impact Factor
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ABSTRACT: of sperm abnormalities in the leopards of Sri Lanka may be related to parallel findings of genetic homozygosity; and (2) decreases in basal and GnRH-stimulated testosterone secretion were related to increases in serum cortisol after electroejaculation or ACTH and were not associated with changes in pituitary gonadotrophin secretion.