Changes in serum thyroid hormone levels and thyroid gland activity of artificially maturing female Japanese eel (Anguilla japonica)

In order to evaluate the involvement of the thyroid gland in reproduction, thyroid functioning was described in female cultivated Japanese eel (Anguilla japonica) in progressive stages of sexual maturation induced by chum salmon pituitary homogenate (SPH) treatment. Serum thyroid hormones, thyroxine (T4) and triiodothyronine (T3) were also measured in each stage. Thyroid gland activity (epithelial cell height) was high before SPH injection (previtellogenic stage), further increasing at the early vitellogenic stage, thereafter decreasing to late vitellogenic and migratory nucleus stages. The profiles of both T3 and T4 changed during vitellogenesis, being high during previtellogenic and early vitellogenic stages, and subsequently declining, thus mimicking thyroid gland activity. These results suggest that the thyroid has relation with eel ovarian development during artificial maturation.

Evaluation of Thyroid Hormones Levels in Libyan Patients with Chronic Renal Failure before and after Maintenance Hemodialy

Data from recent studies revealed that kidney diseases might affect the thyroid function in various ways. A variety of alterations in thyroid hormone levels and metabolism have also been reported in patients with chronic renal failure (CRF) in some studied population. In addition, it was reported that serum levels of both T3 and T4 might alter immediately after a hemodialysis (HD) treatment than before. Therefore, this study was aimed to investigate the level of triiodothyronine (T3) and thyroxine (T4) in CRF Libyan patients before and after HD. This study was carried out on 46 CRF patients (30 males and 16 females) with a mean age of 47.46 ± 15.75 years. These patients were treated at the hemodialysis unit of Educational Central Zelitin Hospital, Zelitin, Libya. None of these patients apparently have any thyroid problems and no history of drug intake that may affect thyroid function. Blood samples were taken from each patient to measure serum levels of T3 and T4, before and after HD. In addition, the effects of several variables including age, gender, body mass index (BMI), presence of both hypertension and, diabetes mellitus and duration of kidney dialysis on serum levels of T3 and T4 before and after HD were also studied. After HD, there was a statistically significant increase in the serum levels of T3, T4. The age, gender, BMI, duration of kidney dialysis and the presence of hypertension and diabetes mellitus did not have any significant effect on the serum level of T3 and T4 before and after HD. However, the serum levels of T3 and T4 were still in the normal range in these examined patients either before or after HD. From these findings, it can be concluded that these CRF patients may be in a euthyroid state, because the serum levels of T3 and T4 were in the normal range. In addition, HD was seemed to improve the T3 and T4 thyroid hormone concentrations, suggesting that HD might activate the secretion of thyroid gland and catabolism. The other variables did not play any role in thyroid hormone levels in these patients either before or after HD. It is highly recommended that large scale evaluation of thyroid hormone levels in Libyan CRF patients is performed by more patients, especially elderly patients.

Effect of estradiol-17β on pituitary-thyroidal axis of Japanese eel (Anguilla japonica)

The effect of estradiol-17β (E2)treatment on the pituitary-thyroidal axis has been investi- gated in female Japanese eels in seawater. The eels were injected with 1 mg/kg body weight (BW) weekly for two to eight weeks; another group was treated with 5 mg/kg BW weekly for eight weeks and sacrificed three days after the last injection. In the pituitary, using RT-PCR systern, the thyroid stim- ulating hormone 3 subunit mRNA (TSHβ MRNA) level is slowly increased in the low-dose E2 treatment group. A significant increase in values occurred after eight weeks E2 injections. The histological structure of the thyroid follicles suggests a hypo-activity as shown by a reduced epithelial cell height in eels injected with E2 after six and eight times, and eventually reached a minimum level after eight weeks. Using ra- dioimmunoassay of thyroxine (T4),triiodothyronine (T3) in the serum, a slowly decrease of both hor- mones is demonstrated. On the other hand, the TSHβ mRNA level is significantly increased from initial in the high-dose E2 treatment group. The histological structure of the thyroid follicles suggests a hypo- activity, and a sharp decrease of the both hormones is also indicated. These data suggest that the expres- sion of TSHβ mRNA level is increased and thyroid hormone release is depressed by E2, the effects de- pend upon E2 inection period and dose. Furthermore, E2 could not directly influence the TSHβ mRNA expression and, TSH transcription might be controlled by a negative feedback of thyroid hormone.

INTRAUTERINE GROWTH RETARDATION AT FULL TERM PREGNANCIES WITH ENDOCRINE FACTORS

Objective To investigate the relationship between intrauterine growth retardation (IUGR) and endocrine parameters so as to assess the effects or the main endocrine ractors on IUGR. The concentrations of growth hormone(GH), insulin, T3, T4 and TSH were measured in umbilical cord blood, amniotic fluid and maternal serum.Methods The samples were collected from 23 pregnant women who were diagnosed as the full term IUGR, 42 normal full term pregnant women with normal infants’ weight were taken as control. Growth hormone and insulin were measured by radioimmunoassay. T3, T4 and TSH were investigated by micro-radioimmunoassay. Results The concentrations of growth hormone, insulin and T4 in umbilical cord blood were lower in IUGR than that in control group(GH4. 63μ/L vs 7. o1μg/L, insulin 1o. 68μIU/ml vs 31. 44μIU/ml, T487. 39nmol/L vs 138. 1onmol/L. P <o. o5, o. o5 and o. o5, respectively). The TSH concentration in umbilical cord blood was higher in IUGR than in control group (1o. 84μmIU/L vs 5. 75μmIU/L, P <o. o1 ). The concentration of growth hormone in maternal serum and the concentration of insulin in amniotic fluid were also lower in IUGR group than in control group(GH 1. 77μg/L vs 2. 74μg/L,P <o. o1, insulin 5. 84μIU/ml vs 15. 64μIU/ml, P <o. o1). Conclusion This study confirms that full term neonates with IUGR are abnormal in endocrine factors. The inadequacy of growth hormone may be one of the causes of IUGR. The relatlve scarcity of growth hormone and insulin seems to be a factor to compromise the fetus’ metabolism. Besides, the early hypothyrosis of infants with IUGR might protect them from unfavorable environment in the uterine.