archives@tulane.edu / The current set of experiments aimed to explore mechanisms underlying sex differences in impulsive behavior in adult rats and sex differences in structures involved in impulse control. Preliminary studies demonstrated sex differences in adult impulsive action and prepubertal impulsive choice with males making more impulsive responses than females. In our studies, neither prepubertal nor adult gonadectomy, and subsequently a loss of gonadal hormone exposure, had any effect on a sex difference in impulsive action. Neonatal exposure of gonadal hormones in females led to a masculinization of impulsive responding in adulthood and eliminated an observed sex difference. This result demonstrates neonatal gonadal hormones to be an organizing mediator of an adult sex difference in impulsive action. No sex difference was seen in adult impulsive choice across hormone conditions. Analysis of myelin protein levels within the orbitofrontal cortex (OFC), a region important for inhibiting impulsive behavior, revealed adult females to exhibit greater levels of myelin basic protein (MBP) than males. This adult sex difference was revealed to be mediated by organizing effects of pubertal gonadal hormone exposure. Inactivation of indirect pathway projecting striatal neurons, neurons important for inhibition of motor output, via designer receptors exclusively activated by designer drug (DREADD) technology, led to a decrease in impulsive responding in adult males and females, eliminating an observed sex difference. Collectively, these results demonstrate for the first time periods of gonadal hormone driven organization of brain morphology and behavior with implications for sex differences in decision making and impulse control. / 1 / Jeffrey Scott Darling

Thesis (Ph. D.)--University of Chicago, 1942. / Reproduced from type-written copy. "Literature cited": p. 17-18.

This document only includes an excerpt of the corresponding thesis or dissertation. To request a digital scan of the full text, please contact the Ruth Lilly Medical Library's Interlibrary Loan Department (rlmlill@iu.edu).

Le syndrome métabolique (Smet) désigne une combinaison d'anomalies métaboliques (obésité, insulinorésistance, dyslipidémie et hypertension) reliées entre elles, dont l‘origine n‘est pas encore définie. D‘après la littérature, les personnes atteintes du Smet présentent des altérations hormonales et de la qualité de vie, mais ce concept étant relativement récent, peu d‘études se sont intéressées aux effets de l‘activité physique régulière sur ces paramètres. Notre travail se divise en deux parties. Dans un premier temps, nous avons étudié la corrélation entre les concentrations hormonales surrénaliennes plasmatiques et salivaires au repos et à l‘exercice chez les hommes atteints du Smet. Il apparait que la corrélation obtenue au repos n‘est pas altérée de manière significative à l‘exercice. Dans un second temps, nous avons étudié les effets d‘une activité physique régulière contrôlée de 8 semaines sur les réponses hypophysaires, surrénaliennes et androgéniques, ainsi que sur les capacités physiques et la qualité de vie chez des hommes atteints du Smet. Nos résultats montrent qu‘un entraînement aérobie de courte durée ne provoque pas de changement anthropométrique mais induit une diminution significative du cortisol salivaire au repos sans modifier les autres concentrations hormonales. Par ailleurs, les capacités physiques et la dimension psycho-sociale de la qualité de vie sont significativement améliorées. Ces données confirment l‘effet bénéfique de l‘activité physique régulière sur les capacités physiques et la qualité de vie, tout en laissant supposer que le cortisol salivaire serait un marqueur précoce signant l‘amélioration des capacités physiques chez les sujets atteints du Smet. D‘autres études, incluant des cohortes plus larges et des durées de réentraînement à l‘effort plus importantes, seraient nécessaires pour compléter ce travail. / The metabolic syndrome (Mets) is a cluster of metabolically related abnormalities (abdominal obesity insulin resistance, dyslipidemia and hypertension), with no obvious defined cause. In the literature, individuals with Mets seem to have hormonal and quality of life alterations, but this concept is relatively recent and few studies have investigated the effects of regular physical activity on these parameters. Our work divides into two parts. First, we studied the correlation between plasmatic and saliva adrenocortical hormonal at rest and during exercise in men with Mets. It appears that the correlation obtained at rest is maintained during exercise. Secondly, we studied the effects of 8 weeks of controlled regular physical activity on the pituitary, adrenocortical and androgenic hormones, physical capacity and quality of life in men with Mets. Our results show that aerobic exercise training does not induce anthropometric modifications but decreases significantly basal saliva cortisol without any other hormonal change. In parallel, physical capacity and psychosocial impact dimension of quality of life are significantly improved. These data confirm the beneficial effect of regular physical activity on physical capacity and quality of life. It is tempting to suggest that saliva cortisol could be an early marker reflecting improvement of physical capacities in individuals with Mets. Further works with larger cohort and longer training programs are required to complete this work.

Regulated survival, proliferation and differentiation of cells in the nervous system is crucial for development. Much of regulation is controlled by hormones. There is abundant evidence that a member of the glucagon superfamily, pituitary adenylate cyclase-activating polypeptide (PACAP), is important in this process. PACAP functions have been described in the peripheral and central nervous systems of many species. Although the primary function of PACAP is not known, its high conservation and presence in all species examined to date suggest it is vital to normal development. My thesis objective was to determine the response of early CNS neuroblasts to PACAP, in conjunction with another glucagon superfamily member, growth hormone releasing hormone (GHRH). GHRH is best known for causing release of growth hormone from the pituitary, but it also has functions in nervous system development. Because PACAP and GHRH are encoded on the same gene in non-mammalian vertebrates, it is possible that they have similar or coordinated functions. PACAP affects development by altering levels of proliferation and differentiation and decreasing apoptosis. For these reasons, I focused my research in these areas. Using neuroblast-enriched cultures from embryonic day 3.5 chick, my first goal was to show that PACAP and GHRH affected these cells. Radioimmunoassays for cAMP revealed that all but one form of PACAP, and only one form of GHRH, caused an increase in cAMP relative to controls. As to the former, comparison of differing PACAP structures suggested that conservation at the amino terminus was important in binding the hormone to the receptor. The fact that PACAP, but not GHRH, increased cAMP, indicated that evolution of PACAP and GHRH had altered their functions. Chick neuroblasts were also shown to produce PACAP and its primary receptor, suggesting an autocrine/paracrine role for PACAP. My next goal was to examine the nature of the downstream effects of increased cAMP. To study cell cycle, I developed a protocol using proliferating cell nuclear antigen (PCNA) and propidium iodide (PI), in fixed cell populations. PCNA is present in low amounts in non-cycling cells, but rises sharply in actively proliferating cells. The PI helped delineate cell cycle compartments, because in permeabilized cells it binds to and quantifies DNA. Changes in G0, G1, S and G2/M were recorded using flow cytometry. Because the cells were producing PACAP and most were cycling, rather than add more PACAP I chose to block the PACAP receptor. This caused cell cycle exit. I also blocked the cell cycle at two points, and showed that exogenous PACAP could release some cells from the block, and return them to cycling. PACAP affected apoptosis also, but because the protocol was not designed to measure this, I adopted another protocol using flow cytometry. With live cells, and fluorescein diacetate, which is retained and fluoresces in healthy cells, and PI, which enters only cells with damaged membranes, I used the characteristic of apoptotic cells to die with membranes intact to confirm increased apoptosis when the PACAP receptor was blocked. This left the question of whether PACAP affected differentiation. The cell cycle protocol had shown some cells were still quiescent, not dying, at 24 h, so I hypothesized that they might be differentiating. I used proteomics to test this. With isotope-coded affinity tagged (ICAT) analysis, I measured changes in protein content in cells that had been treated with the receptor blocker, compared to control. This confirmed previous work and my hypothesis that some cells were differentiating. Because this technique is not commonly used in molecular biology, I also evaluated the effectiveness of the technique. My work showed that endogenous PACAP keeps chick neuroblasts alive and cycling, but will allow some to differentiate rather than die, when the hormone is withdrawn. Obviously, PACAP plays a crucial role in early chick brain development. / Graduate

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Myosin heavy chain (MHC) isoforms in vertebrate striated muscles are encoded by a highly conserved multigene family. Seven sarcomeric MHCs are known to be expressed in cardiac and skeletal muscles of the rat. These isoforms show distinct patterns of tissue-specific expression which are hormonally and developmentally regulated. Thyroid hormone has been shown to regulate the expression of the ventricular isoforms by causing an accumulation of alpha-MHC and a repression of beta-MHC. Alterations in thyroid status have also been reported to affect MHC isoforms in skeletal muscles. The first part of this study describes the development of a dot-blot assay with which to measure the levels of the sarcomeric MHC mRNAs. This assay was utilized in part two of this dissertation to analyze the effects of thyroid hormone administration on the expression of MHC and actin mRNAs in ventricular muscle, as well as in representative fast and slow skeletal muscles of the hypothyroid rat. The results indicate that expression of all of the MHC genes is regulated by thyroid hormone in a highly complex, tissue specific manner. Also, thyroid hormone caused transient increases in the expression of cardiac actin mRNA in the ventricle, but no actin isoform transitions were observed in any muscle type. The third portion of this dissertation describes the development of a cultured cell system that has been used to analyze changes in MHC and alpha-actin gene expression in response to thyroid hormone in vitro. Cultured primary fetal cardiomyocytes were found to express only the cardiac MHC and actin isoforms. In addition, the alpha- and beta-MHC isoforms were found to be regulated by thyroid hormone in a similar manner to that observed in the intact rat ventricle. In the final portion of this study, the promoter region of the thyroid hormone inducible gene, alpha-MHC, was isolated and ligated to the bacterial chloramphenicol acetyltransferase gene. Chimeric genes were utilized in transfection studies and found to be thyroid hormone inducible. The results suggest that DNA sequences in the 5' flanking region of the alpha-MHC gene are sufficient to mediate hormone induction of the gene.

Thesis (Ph.D.)--Boston University. Missing pages 78, 79. / The prime purpose of this investigation was the development of a rapid and sensitive procedure for the assay of estrogenic hormones. The advent of gas chromatography offered a possible solution to this problem. A pre-requisite of any gas chromatographic method is that the compounds to be chromatographed be volatile and thermally stable at the temperatures of vaporization and separation in the presence of the eluting gas. Accordingly, the thermal stability of certain free and acetylated estrogens was studied. The results of these studies indicated that decomposition was minimal when small quantities were subjected to gas chromatographic separation. Estrogen acetates were found to be stable up to 340°C by infrared spectroscopy, ultraviolet spectroscopy and by an evaluation of the gas chromatographic peak symmetry. Once suitable derivatives had been found, the parameters of separation and detection were evaluated. The optimum conditions for separation were found to be: 1) a temperature of 240°-280°C, 2) column length of 3 feet, 3) a silicone grease liquid phase, 4) flow rates of 50-500 cc/min, and 5) non-polar solvents. The lower limits of detector sensitivity were found to be 0.2ug for a sr90 detector and lOOug for the thermal conductivity cell detector. The ionization detector responded linearly in the range of 0.2 to 25 ug. The thermal conductivity cell detector responded linearly in the range of 100 to 400 ug. In order to have a quantitative procedure, it was necessary to determine the optimal conditions for the preparation of the estrogen acetates. It was found by means of gas chromatography, infrared spectroscopy and ultraviolet spectroscopy that estrone was converted to its acetate in 86-90 per cent yield in 2 x 10-3 M solutions in one hour at 65C. Estradiol, under the same conditions was found to be converted in 92 percent yield to the diacetate. The remaining 8 per cent was found to be estradiol-3- acetate. By allowing this reaction to proceed overnight only two per cent of the monoacetate was found. Estriol, in reactions which were carried out under similar conditions, was found to be converted in 98 per cent yield to the triacetate. In order to develop a urinary assay procedure, recovery studies from water and acid hydrolyzed urine, were carried out. The results indicated a 75-80 percent recovery of estrone and estradiol and a 90-95 per cent recovery of estriol. The lowest concentration studied was the recovery of steroid from a solution containing 1 ug/ml. Studies at this lower concentration showed that the recoveries were independent of concentration. The method described above has the advantage of chemical specificity, rapidity and reproducibility. As yet, it has not been developed to its highest sensitivity, however, coupled with prepurification procedures and with advances in instrumentation, it appears that the method will become useful for low level estrogen determination in biological media.