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Start Over Creator Illnerová, H.

2. 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

3. Resetting of the mammalian circadian clock through lowering of the amplitude: rat pineal N-acetyltransferase rhythm as a model

Creator:
Illnerová, H.
Type:
article, model:article, and TEXT
Subject:
circadian pacemaker, amplitude, resetting, N-acetyltransferase, and rat
Language:
English
Description:
During resetting of the mammalian circadian clock, not only phase of the clock is shifted, but amplitude of overt rhythms driven by the clock may be temporarily reduced or even abolished. The present paper is aimed to elucidate the mechanism of amplitude reduction of the overt circadian rhythm in the rat pineal N-acetyltransferase (NAT). The rhythm has two phase markers, namely the time of the evening NAT rise and that of the morning decline. When the phase relationship between both markers is compressed drastically, the NAT rise may occur just close to or at the time of the decline and consequently the NAT rhythm with a full amplitude cannot be expressed. Such a compression may occur in two ways: either animals are subjected to a considerable advance in the light onset which phase advances the morning NAT decline and at the same time phase delays the evening NAT rise, or they are subjected to a considerable delay in the light offset, which primarily phase delays more the NAT rise than the decline. While in the former case the phase markers move in opposite directions, in the latter case they move in the same direction, but to a different extent. The data suggest a complex structure of the underlying clock.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

4. Seasonal Molecular Timekeeping Within the Rat Circadian Clock

Creator:
Sumová, A., Bendová, Z., Sládek, M., Kováčiková, Z., and Illnerová, H.
Type:
article, model:article, and TEXT
Subject:
Suprachiasmatic nucleus, Rat, and Photoperiod
Language:
English
Description:
In temperate zones duration of daylight, i.e. photoperiod, changes with the seasons. The changing photoperiod affects animal as well as human physiology. All mammals exhibit circadian rhythms and a circadian clock controlling the rhythms is located in the suprachiasmatic nucleus (SCN) of the hypothalamus. The SCN consists of two parts differing morphologically and functionally, namely of the ventrolateral (VL) and the dorsomedial (DM). Many aspects of SCN-driven rhythmicity are affected by the photoperiod. The aim of the present overview is to summarize data about the effect of the photoperiod on the molecular timekeeping mechanism in the rat SCN, especially the effect on core clock genes, clock-controlled genes and clock-related genes expression. The summarized data indicate that the photoperiod affects i) clock-driven rhythm in photoinduction of c-fos gene and its protein product within the VL SCN, ii) clock-driven spontaneous rhythms in clock-controlled, i.e. arginine-vasopressin, and in clock-related, i.e. c-fos, gene expression within the DM SCN, and iii) the core clockwork mechanism within the rat SCN. Hence, the whole central timekeeping mechanism within the rat circadian clock measures not only the daytime but also the time of the year, i.e. the actual season.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public