Sexual dimorphism in the catecholamine-containing thymus microenvironment: a role for gonadal hormones.
The study was undertaken to explore whether there were: i) apart from neural and circulatory, some other sources of catecholamines (CAs) in rat thymus and ii) gender-specific differences in thymic CA levels, and if so to elucidate the role of sex steroids in this phenomenon. Tyrosine hydroxylase (TH) immunoreactivity was found in thymocytes and thymic epithelial cells (some of which showed morphological features of nurse cells). The density of CA-synthesizing cells was greater in male than in female rats. Noradrenaline (NA), but not dopamine (DA), was detected in thymocytes. NA and DA levels in thymi, and the NA level in thymocytes, were higher in male rats. To explore the putative role of sex steroids in this dichotomy in the thymi of adult rats gonadectomized (Gx) or sham-Gx at the age of 30 days the density of TH+ cells and CA levels were measured. Gonadectomy abolished sexual dimorphism in the density of thymic TH+ cells (diminishing their density in male rats) and thymic CA levels (the NA levels were reduced in rats of both sexes and also the DA level in male rats). Therefore, it can be assumed that testicular and ovarian hormones control thymic NA and DA levels via different mechanisms. Moreover, in Gx rats, despite the decrease in the overall thymic NA level, an increase in the thymocyte NA level was found indicating that gonadal hormones exert differential effects on the NA level in distinct thymic cellular compartments.
Pilipović
Ivan
I
Immunology Research Centre Branislav Janković, Institute of Immunology and Virology Torlak, Belgrade, Serbia.
Vidić-Danković
Biljana
B
Perisić
Milica
M
Radojević
Katarina
K
Colić
Miodrag
M
Todorović
Vera
V
Leposavić
Gordana
G
D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D001921:Brain / Q000033:anatomy & histology / Q000378:metabolism; D017252:CD3 Complex / Q000378:metabolism; D002369:Castration / Q000379:methods; D002395:Catecholamines / Q000378:metabolism*; D002460:Cell Line; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D003713:Dendritic Cells / Q000378:metabolism; D004563:Electrochemistry / Q000379:methods; D004847:Epithelial Cells / Q000378:metabolism; D005260:Female; D005786:Gene Expression Regulation; D042341:Gonadal Hormones / Q000502:physiology*; D008297:Male; D051381:Rats; D012727:Sex Characteristics; D013950:Thymus Gland / Q000166:cytology* / Q000378:metabolism*; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism
D017252:CD3 Complex; D002395:Catecholamines; D042341:Gonadal Hormones; D014446:Tyrosine 3-Monooxygenase