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Start Over Creator Štrbák, V.

2. Effects of dexamethasone on pancreatic growth and thyroliberin (TRH) content in neonatal rat pancreas

Creator:
Benický, J. and Štrbák, V.
Type:
article, model:article, and TEXT
Subject:
pancreas, ontogenesis, thyrotropin-releasing hormone, and dexamethasone
Language:
English
Description:
Thyrotropin-releasing hormone (TRH) is also present in pancreatic B-cells and its role and regulation here remain unclear. The rat pancreas displays a peculiar ontogenetic pattern for TRH with a rapid increase after birth up to postnatal day 3 when TRH peak is reached. In the present study, dexamethasone (DXM) treatment (1 ¿/g/lOOg BW/day) resulted in an increase of pancreatic weight and retardation of the peak of pancreatic TRH concentration by two days. The TRH-degrading system (either in the 10 000 x g supernatant or in the pellet of pancreatic homogenate) was not stimulated by in vivo DXM treatment. In DXM-treated rats, plasma TSH levels were significantly decreased after postnatal day 1. Plasma glucose concentration was increased on day 1 (i.e. 24 h after the first DXM injection) and decreased to the control level on postnatal day 3. Pancreatic insulin levels were decreased on postnatal day 3 compared to the controls. These results indicate that DXM affects TRH in the neonatal rat pancreas; this effect is probably not mediated through modulation of TRH-degrading activity. The stimulation of pancreatic growth after DXM treatment might be related to the effect on the TRH system.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

3. Milk-borne hormones: possible tools of communication between mother and suckling

Creator:
Koldovský, O., Illnerová, H., Macho, L., Štrbák, V., and Štěpánková, R.
Type:
article, model:article, and TEXT
Subject:
mother-pup interaction, thyroxin, thyroid-stimulating hormone, epidermal growth factor, insulin, insulin-like growth factors IGF- I and IGF-II, somatostatin, melatonin, and protective role of milk-borne factors
Language:
English
Description:
Early studies suggested endocrine type mother-pup interaction: 13M administered to suckling rats appeared via the urine of the suckling and mother's milk in the circulation of litter mates who were not injected with iodine; levels of thyroxin in rat milk were influenced by the status of the thyroid gland of the lactating rat. Administration of TRH (thyrotropin releasing hormone) to lactating mothers led to an appearance of unaltered hormones in the milk and stomach content of sucklings. TSH (thyroid stimulating hormone) or ACTH (adrenocorticotropic hormone) when given orogastrically to suckling rats increased thyroid hormones and corticosterone serum levels in suckling rats. Functional effects of gastrointestinal administration of insulin, bombesin (mammalian analog of gastrin-releasing peptide) and epidermal growth factor (EGF) are reviewed in detail (32 references).
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

4. Thyroid hormone receptor occupancy and biological effects of 3,5,3,-L-triiodothyronine (T3) in GH4C1 rat pituitary tumour cells

Creator:
Filipčík, P., Štrbák, V., and Brtko, J.
Type:
article, model:article, and TEXT
Subject:
GH4C1 rat pituitary cell line, 3,5,3,-L-triiodothyronine, thyroid hormone receptors, receptor occupancy, and biological response
Language:
English
Description:
The GH4C1 pituitary cell line, an excellent model for a thyroid hormone action study, was used for determination of the relationship between thyroid hormone receptor occupancy and intensity of cell proliferation, prolactin (PRL) production, thyrotropin (TSH) inhibition and 3,5,3,-L-triiodothyronine (T3) receptor down-regulation. Nuclear receptor population was progressively occupied by T3 in concentrations ranging from 0.025 to 10.0 nM T3. Bmax ranged from 0.029 fmol/106 cells at the lowest T3 concentration to Bmax = 12.51 fmol/106 cells at the highest concentration. Each of the observed biological events is operative within distinct dose-response ranges in cultured GH4C1 cells. The maximal biological response (except the TSH inhibition and T3 receptor down-regulation) does not require the occupation of the whole nuclear receptor population by T3 and the intensity of none of the responses studied was directly proportional to thyroid hormone receptor occupancy.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public