Publications by authors named "James P Porter"

Osteoarthritis (OA) is a degenerative joint disease characterized by inflammatory degradation of articular cartilage and subchondral bone. Wogonin, a compound extracted from the plant (colloquially known as skullcap), has previously been shown to have direct anti-inflammatory and antioxidative properties. We examined the pain-reducing, anti-inflammatory, and chondroprotective effects of wogonin when applied as a topical cream.

View Article and Find Full Text PDF

In bovine adrenal zona fasciculata (ZF) and NCI-H295R cells, interleukin-6 (IL-6) increases cortisol release, increases expression of steroidogenic acute regulatory protein (StAR), cholesterol side chain cleavage enzyme (P450scc), and steroidogenic factor 1 (SF-1) (increases steroidogenic proteins), and decreases the expression of adrenal hypoplasia congenita-like protein (DAX-1) (inhibits steroidogenic proteins). In contrast, IL-6 decreases bovine adrenal zona reticularis (ZR) androgen release, StAR, P450scc, and SF-1 expression, and increases DAX-1 expression. Adenosine monophosphate (AMP) activated kinase (AMPK) regulates steroidogenesis, but its role in IL-6 regulation of adrenal steroidogenesis is unknown.

View Article and Find Full Text PDF

Mechanisms of interleukin-6 (IL-6)-induced cortisol release (CR) were investigated by exposing H295R cells to IL-6 and determining mRNA/protein expression (PCR/western blots) for steroidogenic enzymes (SE), steroidogenic acute regulatory protein (StAR), steroidogenic factor-1 (SF-1) (enhances SE/StAR expression), activator protein 1 (AP-1) (regulates SE/StAR expression) and adrenal hypoplasia congenita-like protein (DAX-1) (inhibits SE/StAR expression). Promoter activity of StAR (SPA) was measured by a luciferase-coupled promoter. Cortisol release was increased by 10ng/mL IL-6 (24h P<0.

View Article and Find Full Text PDF

Cigarette smoke exposure increases lung ceramide biosynthesis and alters metabolic function. We hypothesized that ceramides are released from the lung during cigarette smoke exposure and result in elevated skeletal muscle ceramide levels, resulting in insulin resistance and altered mitochondrial respiration. Employing cell and animal models, we explored the effect of cigarette smoke on muscle cell insulin signaling and mitochondrial respiration.

View Article and Find Full Text PDF

We recently reported that feeding Sprague Dawley rats a high-salt diet during pregnancy programmed an exaggerated pressor and tachycardic response to restraint in adult female offspring. In the present investigation, a pharmacologic approach was used to determine the contribution of the sympathoadrenal system to the exaggerated response. Injection of a cocktail containing a ganglionic blocker (chlorisondamine) and a beta-adrenoceptor antagonist (propranolol) prevented the stress-induced tachycardia and increase in blood pressure and abolished the difference between high-salt and normal-salt offspring.

View Article and Find Full Text PDF

The release of adrenal steroids during acute stress is primarily regulated by adrenocorticotropic hormone (ACTH). In contrast, during chronic inflammatory stress additional factors are involved in regulating adrenal function. Leukemia inhibitory factor (LIF) is a pleiotropic cytokine that increases ACTH release from the pituitary.

View Article and Find Full Text PDF

Several animal models have been developed to study fetal programming of hypertension. One model involves feeding high-salt (HS) diet to rats before and during pregnancy, during lactation, and after weaning for 10 days. In the present investigation, we limited HS diet to the prenatal period in an attempt to find a narrower critical window for fetal programming.

View Article and Find Full Text PDF

The early discontinuation of the Women's Health Initiative trial evaluating the effects of estrogen plus progestin due to concerns about the risk-benefit ratio of this steroid combination therapy emphasizes the need to examine alternative methods of estrogen replacement. One such alternative is isoflavone consumption of soy-derived dietary phytoestrogens that have received prevalent usage due to their ability to decrease age related disease (cardiovascular and osteoporosis), hormone-dependent cancers (breast and prostate), and peri- and postmenopausal symptoms. Differences in dietary phytoestrogen consumption result in large variations in somatic phytoestrogen content.

View Article and Find Full Text PDF

Aging humans and rats have a reduced renal vascular constriction response to stress, change in posture, or exercise. In this study, renal interlobar arteries from 9- (intermediate age) to 15-month-old (aging) male Wistar rats constricted less to alpha-adrenergic agonists than those of 4-month-old (young adult) rats. The reduced contraction to A61603 (alpha 1 A agonist) was similar to that to norepinephrine and phenylephrine.

View Article and Find Full Text PDF

BACKGROUND: Phytoestrogens derived from soy foods (or isoflavones) have received prevalent usage due to their 'health benefits' of decreasing: a) age-related diseases, b) hormone-dependent cancers and c) postmenopausal symptoms. However, little is known about the influence of dietary phytoestrogens on regulatory behaviors, such as food and water intake, metabolic hormones and neuroendocrine parameters. This study examined important hormonal and metabolic health issues by testing the hypotheses that dietary soy-derived isoflavones influence: 1) body weight and adipose deposition, 2) food and water intake, 3) metabolic hormones (i.

View Article and Find Full Text PDF

There is increasing evidence that early life stressors may program blood pressure control mechanisms such that the risk for cardiovascular disease in later life is increased. In the present investigation, the effect of repeated restraint/heat stress during the two-week period immediately after weaning on baroreflex function was determined and the contribution of brain angiotensin II (ANG II) to the changes was assessed in young, conscious, freely moving Sprague Dawley rats. In rats two weeks post weaning, basal MAP was significantly higher and basal HR significantly lower than rats tested immediately after weaning.

View Article and Find Full Text PDF

We recently reported that intracerebroventricular infusions of ANG II decreased food intake and increased energy expenditure in young rats. The aim of the present study was to determine if intracerebroventricular ANG II has similar effects in adult rats. The time course of the effect was also investigated with the idea that at earlier time points, a potential role for increased hypothalamic expression of corticotropin-releasing hormone (CRH) in the anorexia could be established.

View Article and Find Full Text PDF

In the present investigation we sought to determine if a perinatal high-salt treatment affects blood pressure at an early age (30 days), and if so, to determine the mechanisms responsible for the hypertension. Pregnant dams were given an 8% NaCl diet [high-salt (HS) rats] during the final one-third of gestation and throughout the suckling period. After weaning, the pups continued to receive the high-salt diet until testing at age 30 days.

View Article and Find Full Text PDF

Autoantibodies that react with double-stranded DNA (dsDNA) are a hallmark for diagnosis of systemic lupus erythematosus (SLE) and are also considered the pathogenic subset that is most associated with lupus nephritis. As an agent to remove the pathogenic dsDNA antibodies from the circulation of SLE patients, we are developing an antigen-based heteropolymer (AHP). The AHP consists of a monoclonal antibody to the complement receptor (CR1) cross-linked to salmon testis dsDNA to effect clearance of anti-DNA antibodies by binding them to erythrocyte CR1.

View Article and Find Full Text PDF

Systemic infusion of ANG II decreases body weight and food intake and increases energy expenditure. We recently reported that young rats receiving a 1-week intracerebroventricular (i.c.

View Article and Find Full Text PDF