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The effects of excess dietary calcium on bone growth were quantified in 44 ewes fed ad libitum diets that contained one of four levels of dietary calcium (0.37, 0.56, 1.13 and 1.80%) and 0.42% phosphorus. Animals were slaughtered at one of six ages, circulating concentrations of hormones and minerals were measured and bone morphometry was evaluated. None of the diets impaired normal bone growth of the metacarpal as evaluated by overall length, cortical index and growth plate width. Circulating plasma concentrations of calcium and gastrin increased as dietary calcium levels increased, but all values were within the normal range for sheep. Plasma phosphorus was unaffected by the level of dietary calcium. Diet had no affect on T3, T4 or estradiol-17 beta. Age significantly (P less than 0.05) affected the metacarpal length, growth plate width and circulating calcium and phosphorus. The metacarpal in these ewes was 95% of mature length by 172 d of age. Attainment of mature length preceded growth plate closure by slightly over 300 d. These results demonstrate that elevated dietary calcium levels do not adversely influence bone growth and that the presence of an intact growth plate does not infer that further bone growth will occur.

Rate of gain by final weight response surfaces for gain of empty body water, protein, lipid and ash were defined with data from 62 male Sprague-Dawley rats. Rats were fed for 21 days at 100, 88, 76, 64, 52 or 40% of ad libitum intake within each of five initial weight groups ranging from 84 to 286 g. Forty additional rats were killed at the beginning of the growing period to provide initial estimates of amount and composition of empty body weight. Water in the gain decreased (P less than 0.05) and lipid increased (P less than 0.05) with increasing final weight. Gains of protein and ash were not significantly affected by final weight. Gains of water, protein and lipid increased (P less than 0.05) linearly with increasing rates of gain. The relationship between rate of gain and composition of gain was not affected by different final weights. Averaged across final weight, at all rates of gain each gram of gain was composed of about 66.9% water, 18.8% protein, 10.6% lipid and from 1.0 to 2.5% ash. Thus, each additional unit of gain per unit time was composed of the same amount of water, protein, lipid and about the same amount of ash. Therefore, over the stage of growth examined, these results demonstrate that the rates at which rats grow do not influence the composition of their gain to a particular weight.

The Jar choriocarcinoma cell line was used as an in vitro placental cell model to determine the effects of polypeptide growth factors on hCG beta secretion. Epidermal and fibroblast growth factor (FGF) treatment of serum-free cultures stimulated hCG beta secretion 2.5- and 4.0-fold over basal serum-free control levels within a 15-h incubation period. Insulin-like growth factor I, nerve growth factor, and transforming growth factor-beta had no significant effect on hCG beta secretion. FGF at concentrations as low as 0.125 ng/ml significantly elevated medium hCG beta levels without increasing cell number or total cellular protein. FGF stimulation of secretion was not detectable until 2 h of treatment. Intracellular hCG beta remained constant (23%) relative to total hCG beta (cell plus medium) as total hCG beta increased 3-fold, suggesting that FGF stimulated de novo hCG beta synthesis. Insulin significantly augmented the FGF-induced hCG beta stimulation without stimulating hCG beta production itself.

© 2016 The Author(s). Background: Gonadectomy is one of the most common procedures performed on dogs in the United States. Neutering has been shown to reduce the risk for some diseases although recent reports suggest increased prevalence for structural disorders and some neoplasias. The relation between neuter status and autoimmune diseases has not been explored. This study evaluated the prevalence and risk of atopic dermatitis (ATOP), autoimmune hemolytic anemia (AIHA), canine myasthenia gravis (CMG), colitis (COL), hypoadrenocorticism (ADD), hypothyroidism (HYPO), immune-mediated polyarthritis (IMPA), immune-mediated thrombocytopenia (ITP), inflammatory bowel disease (IBD), lupus erythematosus (LUP), and pemphigus complex (PEMC), for intact females, intact males, neutered females, and neutered males. Pyometra (PYO) was evaluated as a control condition. Results: Patient records (90,090) from the William R. Pritchard Veterinary Medical Teaching Hospital at the University of California, Davis from 1995 to 2010 were analyzed in order to determine the risk of immune-mediated disease relative to neuter status in dogs. Neutered dogs had a significantly greater risk of ATOP, AIHA, ADD, HYPO, ITP, and IBD than intact dogs with neutered females being at greater risk than neutered males for all but AIHA and ADD. Neutered females, but not males, had a significantly greater risk of LUP than intact females. Pyometra was a greater risk for intact females. Conclusions: The data underscore the importance of sex steroids on immune function emphasizing a role of these hormones on tissue self-recognition. Neutering is critically important for population control, reduction of reproductive disorders, and offers convenience for owners. Despite these advantages, the analyses of the present study suggest that neutering is associated with increased risk for certain autoimmune disorders and underscore the need for owners to consult with their veterinary practitioner prior to neutering to evaluate possible benefits and risks associated with such a procedure.

Developmental programming of the fetus has consequences for physiologic responses in the offspring as an adult and, more recently, is implicated in the expression of altered phenotypes of future generations. Some phenotypes, such as fertility, bone strength, and adiposity are highly relevant to food animal production and in utero factors that impinge on those traits are vital to understand. A key systemic regulatory hormone is growth hormone (GH), which has a developmental role in virtually all tissues and organs. This review catalogs the impact of GH on tissue programming and how perturbations early in development influence GH function.