Where are gonadal steroids produced

The gonadal arteries are paired vessels that usually originate from the abdominal aorta at the level of second lumbar vertebra. In 5–20% of cases, the gonadal artery has a high origin (superior to L2) and in 5–6% of cases it originates from the main or accessory renal artery. The latter is referred to here as an aberrant gonadal artery. Ninety-eight kidneys of 50 healthy potential renal transplant donors were prospectively studied by conventional angiography. The renal artery, either main or accessory, was detected and individually injected to highlight their perihilar divisions and possible extrarenal branches. The gonadal arteries were recorded if they originated from the renal arteries. We found that 39% ( n = 38) of kidneys had at least one accessory renal artery. In 14 sides (14% of kidneys), the gonadal artery (11 right and 3 left) originated from the renal artery, either main ( n = 5) or accessory ( n = 9). Ten out of 14 kidneys with an aberrant gonadal artery had an associated accessory renal artery. In nine cases, the gonadal artery originated from the accessory renal artery, and in one case, although it originated from the main renal artery, the same kidney had an accessory arterial supply. The results of this study demonstrate that aberrant gonadal arteries tend to originate from kidneys that possess an accessory arterial supply. We hypothesize that aberrancies of the gonadal artery are a part of a common embryologic error resulting in the persistence of the future accessory renal arteries. We believe that this study is the first to hypothesize and study such an association with these arterial anomalies of the renal pedicle. Clin. Anat. 20:428–432, 2007. © 2006 Wiley-Liss, Inc.

Bi-directional relationships operate between the hypothalamic-pituitary-gonadal axis and the immune system. Cytokines, peptide hormones and their shared receptors/ligands are used as a common biological language for communication within and between the immune and neuroendocrine systems. Such communication suggests an immunoregulatory role for the brain and a sensory function for the immune system. We used a radioimmunoassay to measure the concentrations of steroid hormones (cortisol, testosterone, estradiol and progesterone) and pituitary hormones [follicle stimulating hormone (FSH), luteinizing hormone (LH) human chorionic gonadotropin (HCG) and prolactin] in peripheral blood plasma from 78 young Gabonese women with chronic filarial infections. We used an enzyme-linked immunosorbent assay to determine the concentrations of four proinflammatory cytokines [tumor necrosis factor-alpha (TNF-alpha), gamma interferon (IFN-gamma), interleukin-1 (IL-1) and IL-6] in the same plasma samples. Progesterone was unchanged and all other steroid hormone plasma concentrations were lower in microfilaremic women than in amicrofilaremic women. The concentration of LH was higher in amicrofilaremic women, whereas the prolactin concentration was higher in microfilaremics. The plasma concentrations of TNF-alpha, IFN-gamma, IL-1 and IL-6 were higher in microfilaremic women. A strong negative correlation was found between the steroid and pituitary hormones and the pro-inflammatory cytokines. Conversely, a strong positive correlation was found between prolactin and the same cytokines. These data provide first evidence of immune system and hormonal system disturbance during chronic filarial infections and suggest that the observed imbalance should be taken into account in the diagnosis and treatment of filarial infections.

Plants which reproduce sexually also have gametes. However, since plants have an alternation of diploid and haploid generations some differences exist. In flowering plants the flowers use meiosis to produce a haploid generation which produce gametes through mitosis. The female haploid is called the ovule and is produced by the ovary of the flower. When mature the haploid ovule produces the female gamete which are ready for fertilization. The male haploid is pollen and is produced by the anther , when pollen lands on a mature stigma of a flower it grows a pollen tube down into the flower. The haploid pollen then produces sperm by mitosis and releases them for fertilization.

Where are gonadal steroids produced

where are gonadal steroids produced


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