Crossbred steers (n = 252, BW = 379 +/- 28 kg) were allotted to 42 pens in a 2 x 3 factorial arrangement of treatments: control or steroid implant (STR; estradiol benzoate+progesterone [three lighter blocks reimplanted on d 84] and trenbolone acetate [reimplanted on d 63]), and either 0, 80, or 160 mg/wk of recombinant bovine somatotropin (bST). Steers were adapted to the finishing diet (12% roughage equivalent, 13% CP) before the start of the experiment and fed for 84 or 119 d. Blood samples were taken on d 0, 14, 28, 56, and 84 for plasma urea N (PUN), serum somatotropin (ST), plasma insulin-like growth factor I (IGF-I), and plasma amino acid assay. Few interactions were noted (P > .1). Gain was increased by both treatments: 1.30 vs 1.66 kg/d for control vs. STR (P < .001) and 1.44, 1.49, and 1.51 kg/d (linear, P = .07) for 0, 80, and 160 mg of bST/wk, respectively. Gain efficiency was also improved: 169 vs 205 g/kg (P < .001) and 177, 189, and 195 g/kg (linear, P < .001), respectively. Average PUN was decreased (P < .001) 29% by STR and decreased 17 and 29% by 80 and 160 mg of bST/wk, respectively (linear, P < .001). Somatotropin decreased mean serum ST compared with controls; STR increased ST 36% compared with controls. Average plasma IGF-I was increased (P< .001) 12% by STR and 13 and 19% (linear, P < .001) by 80 and 160 mg of bST/wk, respectively. Both STR and bST influenced (P < .05) plasma amino acid profiles. Indicators of carcass fatness were decreased linearly (P < .05) by bST; STR implant tended to decrease carcass fatness and increase longissimus muscle area, which was related to carcass weight. The anabolic effects of STR and bST were found to be additive and possibly independent in feedlot steers.

The APS Journal Legacy Content is the corpus of 100 years of historical scientific research from the American Physiological Society research journals. This package goes back to the first issue of each of the APS journals including the American Journal of Physiology, first published in 1898. The full text scanned images of the printed pages are easily searchable. Downloads quickly in PDF format.

GIP (glucose dependent insulinotrophic polypeptide), originally identified as an incretin peptide synthesized in the gut, has recently been identified, along with its receptors (GIPR), in the brain. Our objective was to investigate the role of GIP in hypothalamic gene expression of biomarkers linked to regulating energy balance and feeding behavior related neurocircuitry. Rats with lateral cerebroventricular cannulas were administered 10 μg GIP or 10 μl artificial cerebrospinal fluid (aCSF) daily for 4 days, after which whole hypothalami were collected. Real time Taqman™ RT-PCR was used to quantitatively compare the mRNA expression levels of a set of genes in the hypothalamus. Administration of GIP resulted in up-regulation of hypothalamic mRNA levels of AVP (46.9±4.5 %), CART (25.9±2.7 %), CREB1 (38.5±4.5 %), GABRD (67.1±11 %), JAK2 (22.1±3.6 %), MAPK1 (33.8±7.8 %), NPY (25.3±5.3 %), OXT (49.1±5.1 %), STAT3 (21.6±3.8 %), and TH (33.9±8.5 %). In a second experiment the same set of genes was evaluated in GIPR-/- and GIPR+/? mice to determine the effect of lack of GIP stimulation on gene expression. In GIPR-/- mice expressions of the following genes were down-regulated: AVP (27.1±7.5 %), CART (28.3±3.7 %), OXT (25.2±5.8 %), PTGES (23.9±4.5 %), and STAT3 (8.8±2.3 %). These results suggest that AVP, CART, OXT and STAT3 may be involved in energy balance-related hypothalamic circuits affected by GIP.

No abstract

Vitamin D (VD) & certain flavonoids have been shown to act directly on adipocytes & osteoblasts. In this study, we investigated whether a diet using a combination of flavonoids with VD would inhibit bone loss & decrease adiposity to a greater extent than control or VD alone diets. Ovariectomized (OVX) female rats (12 mo old, N=10, initial BW=240g) were given control (AIN‐93M diet alone), VD (10 IU/kg BW/d) or VD + resveratrol (R: 4, 20, or 100 mg/kg BW/d) + quercetin (Q: 20, 125 or 625 mg/kg BW/d) + genistein (G:16, 64 or 256 mg/kg BW/d) in AIN‐93M diet for 8 wk. After rats were killed, inguinal (I) & retroperitoneal (RP) fat pads were weighed & bones were collected for measurements. The high dose combination treatment (VD+R100+Q625+G256) significantly reduced BW gain (79±5 vs 62±3g, p<0.05), weight of RP+I fat pads (21.8±1 vs 19.8±0.8g, p<0.05) & RP+I fat pads as % of BW (7.5±0.4 vs 6.9±0.4%, p<0.05). Bone mineral density (BMD) & content (BMC) of femora were significantly increased by the high dose combination, although they weren't different from VD alone. However, BMD corrected for BW was significantly greater in the high dose treated group compared to both control & VD groups (4.7±0.05 vs 5.0±0.2 vs 5.6±0.2, p<0.05). We conclude that VD when combined with R, Q & G improved bone density & reduced weight gain & adiposity in OVX female rats compared to control & VD alone. Supported by the GA Research Alliance Eminent Scholar endowment (CAB).