No abstract

To study the response of the adrenal gland of white-tailed deer to exogenous ACTH, eight penned animals (five mature intact males, one mature castrate male, one adult castrate female, and one immature female) were sedated with xylazine and ketamine and then challenged with various doses of ACTH with and without dexamethasone (DX) pretreatment. Plasma concentrations of cortisol and cortiscosterone were determined by radioimmunoassay in serial samples taken from a jugular cannula. Rapid, dose-dependent increases lasting over 5 h were observed after intramuscular injection of 10, 20, or 40 IU of porcine ACTH. The ratio of cortisol to corticosterone varied from 2:1 to 40:1. Maximum cortisol concentrations averaged 14.9, 20.3, and 21.3 μg/dL, respectively. Intravenous infusion of 5 mg of DX induced a rapid decline of cortisol levels. Administration of 20 or 40 IU of ACTH 140 min after DX caused increases of cortisol which were not different from those when ACTH was given alone. It was concluded that (i) xylazine and ketamine immobilization is suitable for study of the adrenal activity in deer, (ii) 20 IU of ACTH elicits maximal response of cortisol and corticosterone, (iii) DX pretreatment can result in minimal cortisol concentrations but its use is not essential for studies of adrenal response to ACTH, and (iv) the adrenal response to ACTH of females and castrate males is similar to that of intact males.

The presence of the sex-linked dwarf gene (dw) in homozygous male (dwldw) and female (dw/-) meat strain chickens is associated with a significant reduction in circulating levels of triiodothyronine (T3). Heterozygous (Dw/dw) male broiler strain chickens have T3 concentrations similar to those in homozygous (Dw/Dw) male broilers. Genetically normal (Dw/Dw) but significantly slower growing roaster strain male meat chickens had consistently higher T3 than the faster growing broilers at all ages in one experiment but only at 8 weeks in a second experiment. Age and not growth rate appears to have a greater influence on serum T3 concentrations in the slow-and fast-growing normal strains. Growth hormone levels were significantly higher in the dwarf chickens at all ages and in all three experiments. The heterozygous and homozygous broilers had similar GH levels and the slow-growing, genetically normal roasters had intermediate concentrations between the broiler and dwarf lines. GH was influenced to a greater extent by the rate of body weight gain than by increasing age in the genetically normal fast and slow growing Strains. 0 1986 Society for Experimental Biology and Medicine. 36

No abstract

The plasma levels of thermolabile (TLAP) and thermostable (TSAP) alkaline phosphatase were investigated in adult male white-tailed deer. Distinct seasonal variation of TLAP (with highly elevated levels in July) were observed, whereas TSAP exhibits low concentration with a small increase in October. No circadian