Physiology Commons^™

An Individualized, Perception-Based Protocol To Investigate Human Physiological Responses To Cooling, Crystal L. Coolbaugh, Emily C. Bush, Elizabeth S. Galenti, E Brian Welch, Theodore F. Towse

Peer Reviewed Articles

Cold exposure, a known stimulant of the thermogenic effects of brown adipose tissue (BAT), is the most widely used method to study BAT physiology in adult humans. Recently, individualized cooling has been recommended to standardize the physiological cold stress applied across participants, but critical experimental details remain unclear. The purpose of this work was to develop a detailed methodology for an individualized, perception-based protocol to investigate human physiological responses to cooling. Participants were wrapped in two water-circulating blankets and fitted with skin temperature probes to estimate BAT activity and peripheral vasoconstriction. We created a thermoesthesia graphical user interface (tGUI) to …

Characterizing Active And Inactive Brown Adipose Tissue In Adult Humans Using Pet-Ct And Mr Imaging, Aliya Gifford, Theodore F. Towse, Ronald C. Walker, Malcolm J. Avison, E Brian Welch

Peer Reviewed Articles

Activated brown adipose tissue (BAT) plays an important role in thermogenesis and whole body metabolism in mammals. Positron emission tomography (PET)-computed tomography (CT) imaging has identified depots of BAT in adult humans, igniting scientific interest. The purpose of this study is to characterize both active and inactive supraclavicular BAT in adults and compare the values to those of subcutaneous white adipose tissue (WAT). We obtained [¹⁸F]fluorodeoxyglucose ([¹⁸F]FDG) PET-CT and magnetic resonance imaging (MRI) scans of 25 healthy adults. Unlike [¹⁸F]FDG PET, which can detect only active BAT, MRI is capable of detecting both active …

Correlations Between Quantitative Fat–Water Magnetic Resonance Imaging And Computed Tomography In Human Subcutaneous White Adipose Tissue, Aliya Gifford, Ronald C. Walker, Theodore F. Towse, E Brian Welch

Peer Reviewed Articles

Beyond estimation of depot volumes, quantitative analysis of adipose tissue properties could improve understanding of how adipose tissue correlates with metabolic risk factors. We investigated whether the fat signal fraction (FSF) derived from quantitative fat–water magnetic resonance imaging (MRI) scans at 3.0 T correlates to CT Hounsfield units (HU) of the same tissue. These measures were acquired in the subcutaneous white adipose tissue (WAT) at the umbilical level of 21 healthy adult subjects. A moderate correlation exists between MRI- and CT-derived WAT values for all subjects, R²=0.54, p<0.0001, with a slope of −2.6, (95% CI [−3.3,−1.8]), indicating that a decrease of 1 HU equals a mean increase of 0.38% FSF. We demonstrate that FSF estimates obtained using quantitative fat–water MRI techniques correlate with CT HU values in subcutaneous WAT, and therefore, MRI-based FSF could be used as an alternative to CT HU for assessing metabolic risk factors.

Estrogen Receptor–Α In Medial Amygdala Neurons Regulates Body Weight, Pingwen Xu, Xuehong Cao, Yanlin He, Liangru Zhu, Yongjie Yang, Kenji Saito, Chunmei Wang, Xiaofeng Yan, Antentor Othrell Hinton Jr., Fang Zou, Hongfang Ding, Yan Xia, Chunling Yan, Gang Shu, San-Pin Wu, Bin Yang, Benjamin Feng, Deborah J. Clegg, Richard Demarchi, Sohaib A. Khan, Sophia Y. Tsai, Francesco J. Demayo, Qi Wu, Qingchun Tong, Yong Xu

Peer Reviewed Articles

Estrogen receptor–α (ERα) activity in the brain prevents obesity in both males and females. However, the ERα-expressing neural populations that regulate body weight remain to be fully elucidated. Here we showed that single-minded–1 (SIM1) neurons in the medial amygdala (MeA) express abundant levels of ERα. Specific deletion of the gene encoding ERα (Esr1) from SIM1 neurons, which are mostly within the MeA, caused hypoactivity and obesity in both male and female mice fed with regular chow, increased susceptibility to diet-induced obesity (DIO) in males but not in females, and blunted the body weight–lowering effects of a glucagon-like peptide-1–estrogen …

Immunolocalization Of G Protein-Coupled Estrogen Receptor In The Rat Epididymis, Griselle B. Martinez-Traverso, Christopher Pearl

Peer Reviewed Articles

Background

Estrogen plays an important role in male reproduction, and males lacking estrogen signaling in the reproductive tissues are infertile. Estrogen signaling is mediated via two nuclear receptors, ERα and ERβ, but it was recently found that a G protein-coupled estrogen receptor (GPER) is present in the testis. It is believed that GPER is a membrane form of the estrogen receptor and mediates non-classical estrogen signaling. However, the cellular localization of GPER in the epididymis is unknown. Therefore, the objective of this study was to determine the cellular and regional expression of GPER in the rat epididymis.

Findings

To localize …

Chronic Hindlimb Ischemia Impairs Functional Vasodilation And Vascular Reactivity In Mouse Feed Arteries, Trevor R. Cardinal, Kyle R. Struthers, Thomas J. Kesler, Matthew D. Yocum, David T. Kurjiaka, James B. Hoying

Peer Reviewed Articles

Vasodilation of lower leg arterioles is impaired in animal models of chronic peripheral ischemia. In addition to arterioles, feed arteries are a critical component of the vascular resistance network, accounting for as much as 50% of the pressure drop across the arterial circulation. Despite the critical importance of feed arteries in blood flow control, the impact of ischemia on feed artery vascular reactivity is unknown. At 14 days following unilateral resection of the femoral–saphenous artery–vein pair, functional vasodilation of the profunda femoris artery was severely impaired, 11 ± 9 versus 152 ± 22%. Although endothelial and smooth muscle-dependent vasodilation were …

A Carboxyl-Terminal Sequence In The Lutropin Β Subunit Contributes To The Sorting Of Lutropin To The Regulated Pathway, Albina Jablonka-Shariff, Christopher A. Pearl, Anna Comstock, Irving Boime

Peer Reviewed Articles

Although synthesized in the same pituitary gonadotropes, the secretion profiles of lutropin (LH) and follitropin (FSH) differ. LH is secreted through a regulated pathway and associated with a bolus release at mid-estrous cycle. In contrast, the majority of FSH is secreted constitutively with an incremental increase until ovulation. Both share an identicalα subunit, and thus theβ subunit contains determinants for sorting into the regulated pathway. Previously, we demonstrated that a hydrophobic carboxyl-terminal heptapeptide of the LHβ subunit (Leu-Ser-Gly-Leu-Leu-Phe-Leu), not found in the FSHβ subunit, influences the intracellular behavior of the LH dimer. To test the hypothesis that the peptide contributes …