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His-D-Trp-Ala-Trp-D-Phe-Lys-NH2 (GHRP-6) stimulated GH release from rat primary pituitary cells in a time- and dose-dependent manner. Stimulation was observed after a 15-min, but not a 4-h, incubation. The concentrations of GHRP-6 required for half-maximal and maximal stimulation were 7 x 10(-9) and 10(-7) M, respectively. GH release induced by GHRP-6 was(More)
Blood and urine were collected from 72 cows in six dairy herds with varying severity of dental and bone fluorotic lesions. Urinary fluoride averaged 5.13 ppm and ranged from 1.04 to 15.7 ppm fluoride. Thyroxine and triiodothyronine in serum decreased with increasing urinary fluoride, eosinophils increased, and cholesterol tended to decrease. Cattle(More)
The objective was to determine whether dairy cows fed supplemental iodine daily at 2.5 or 5.0 mg per kg body weight for 49 wk had altered thyroid status relative to controls fed no supplemental iodine. Average daily dose of iodine was 1.6 and 3.3 g. Iodine as ethylene diamine dihydriodide was fed to Holstein cows beginning at 8 to 10 wk of lactation, for(More)
Ovarian follicular cysts of cattle were defined as follicular structures (larger than or equal to 2.5 cm, diameter) which persisted for 10 days or longer in the absence of functional luteal tissue. Thirty dairy cows with ovarian follicular cysts were allotted to 6 groups (5 cows per group) and each was given 0 (saline solution), 25, 50, 100, 150, or 250 mug(More)
The objective was to determine whether the suckling-induced delay in return to estrus postpartum could be explained by changes in hypothalamic LHRH content or ability of the pituitary to release LH and FSH in response to LHRH or 59 mM K+ in vitro. In addition, serum concentrations of several other hormones were measured. Nine Holstein cows were suckled ad(More)
Forty Holstein-Friesian heifer calves were divided into four groups of ten each and dosed orally with ethylenediamine dihydriodide to provide 0, 50, 250, or 1,250 mg of iodide/animal each day. Five calves in each group were given thyrotropin-releasing hormone at 4-week intervals. Two calves given 1,250 mg of iodide (active ingredient)/day died by 70 days(More)
Suckling causes a delay in onset of estrus and ovulation in cattle postpartum. In addition, the suckling stimulus causes the release of corticoids presumably via ACTH. Since any hormone released by suckling is a potential inhibitor of gonadotropin secretion and/or ovulation, we investigated the effects of ACTH and cortisol on LHRH-induced LH release from(More)