1.Effects of GnRH immunization on the reproductive axis and thymulin.
Su S1, Sun X1, Zhou X1, Fang F2, Li Y1. J Endocrinol. 2015 Aug;226(2):93-102. doi: 10.1530/JOE-14-0720. Epub 2015 May 27.
The bidirectional regulation of thymulin in the reproductive-endocrine function of the hypothalamic-pituitary-gonadal (HPG) axis of rats immunized against GnRH remains largely unclear. We explored the alterations in hormones in the HPG axis in immunized rats to dissect the repressive effect of immunization on thymulin, and to clarify the interrelation of reproductive hormones and thymulin in vivo. The results showed that, in the first 2 weeks of booster immunization, thymulin was repressed when reproductive hormones were severely reduced. The self-feedback regulation of thymulin was then stimulated in later immune stages: the rising circulating thymulin upregulated LH and FSH, including GnRH in the hypothalamus, although the levels of those hormones were still significantly lower than in the control groups. In astrocytes, thymulin produced a feedback effect in regulated GnRH neurons. However, in the arcuate nucleus (Arc) and the median eminence (ME), the mediator of astrocytes and other glial cells were also directly affected by reproductive hormones.
2.The obesity-associated transcription factor ETV5 modulates circulating glucocorticoids.
Gutierrez-Aguilar R1, Thompson A2, Marchand N3, Dumont P3, Woods SC2, de Launoit Y3, Seeley RJ4, Ulrich-Lai YM2. Physiol Behav. 2015 Oct 15;150:38-42. doi: 10.1016/j.physbeh.2015.03.027. Epub 2015 Mar 24.
The transcription factor E-twenty-six version 5 (ETV5) has been linked with obesity in genome-wide association studies. Moreover, ETV5-deficient mice (knockout; KO) have reduced body weight, lower fat mass, and are resistant to diet-induced obesity, directly linking ETV5 to the regulation of energy balance and metabolism. ETV5 is expressed in hypothalamic brain regions that regulate both metabolism and HPA axis activity, suggesting that ETV5 may also modulate HPA axis function. In order to test this possibility, plasma corticosterone levels were measured in ETV5 KO and wildtype (WT) mice before (pre-stress) and after (post-stress) a mild stressor (intraperitoneal injection). ETV5 deficiency increased both pre- and post-stress plasma corticosterone, suggesting that loss of ETV5 elevated glucocorticoid tone. Consistent with this idea, ETV5 KO mice have reduced thymus weight, suggestive of increased glucocorticoid-induced thymic involution.
3.[THYMIC HORMONES, ANTIOXIDANT ENZYMES AND NEUROGENESIS OF BULBUS OLFACTORIUS IN RATS WITH PARKINSONISM: THE EFFECT OF MELATONIN].
Labunets IF, Talanov SA, Vasilyev RG, Rodnichenko AE, Utko NA, Kyzminova IA, Kopjak BS, Podjachenko EV, Sagach VF, Butenko GM. Fiziol Zh. 2015;61(5):35-45.
The adult rats received both neurotoxin 6-hidroxidophamine and neurotoxin and melatonin. It was investigated a link between the disturbances of the brain antioxidant enzymes activity and thymic endocrine function, as possible pathogenic factors of parkinsonism, with changes in the number of neural stem cells (NSC) in the bulbus olfactorius. Rats with motor asymmetry in the apomorphine test and significant damage of the dopaminergic neurons in the-substantia nigra have decreased levels of superoxide dismutase, catalase and glutathione peroxidase activities in striatum (1.3-1.4 times) and blood thymulin content (8 times) compared to control group. On the contrary, examined indices were not changed in rats without motor asymmetry and correspondingly partly damaged neurons. The number of nestin(+)-cells in the bulbus olfactorius of rats without motor asymmetry increased from 91.2% to 99.3% and remained unchanged after melatonin administration course (10 mg/kg during 18 days).
