Prolonged elevation of insulin content in the unicellular tetrahymena after insulin treatment: induction of insulin production or storage?

Abstract

In the unicellular organism, Tetrahymena, the ®rst encounter with an exogeneously given hormone results in hormonal imprinting. This causes an increase of the binding capacity of receptors and the production of the appropriate hormone in the progeny generations of the treated cell. In the present experiments the quantity (using radioimmunoassay) and localization (using confocal laser scanning microscopy) of the immunologically insulin-like material (hereafter insulin) were studied for 10 days after 4 h or 24 h 10 À6 M insulin treatment (hormonal imprinting). Forty-eight hours after both insulin treatments a high quantity of insulin was present in the cells. This value was also signi®cantly increased after 96 h. After 8 days the di€erence to the control was signi®cant only in the 24 h treated group. Confocal microscopy (using antibody to pig insulin) localized insulin in the cell body. The oral ®eld contained extremely high quantities of the endogeneous hormone. Insulin treatment (after 48 and 96 h) caused an elevation of insulin content in general, and speci®c accumulation in the posterior sections of the cell, around the nucleus and in the periphery were observed. Ten days after both treatments only the peripheral region of the cell body and the ciliary row contained more insulin than the control. This means that after insulin treatment the quantity of insulin increases for a lengthy time period which is followed by the expression of insulin in the peripheral region. Insulin contained by Tetrahymena 48 h after imprinting stimulated glucose uptake of rat diaphragm.

Effect of insulin on in vitro fermentation activity of microrganism community of rumen ciliate culture

“…These biologically active molecules can induce and modify the activity of physiological processes such as growth (Christensen, 1993;Christensen et al, 1996aChristensen et al, ,b, 1998Csaba et al, 1985Csaba et al, , 1995Hegyesi and Csaba, 1997;Kristiansen et al, 1996;Shemarova et al, 2002), phagocytosis (Darvas and Csaba, 1990;Ko¨hidai et al, 1995;Kovacs et al, 1996;Schiess et al, 2001), metabolic pathways (Csaba and Lantos, 1976;Csaba and Nagy, 1976;Csaba and Ubornyak, 1982;Ko¨hidai and Csaba, 1985), movement (Csaba and Kovacs, 1993;Ko¨hidai et al, 1994Ko¨hidai et al, , 2000Ko¨hidai et al, , 2002Kovacs et al, 1994;Mugnaini et al, 1995), and secretion activity (Bencsath et al, 1994;Kovacs et al, 1992Kovacs et al, , 1997. Peptide type hormones causing these physiological effects are universal in multicellular systems, but many of them are present in unicellular organisms as well (Csaba and Kovacs, 2000;Csaba et al, 1999;De Pablo et al, 1986;Fulop and Csaba, 1991;Leroith et al, 1980Leroith et al, , 1981Leroith et al, , 1985Schwabe et al, 1983). The latter are not only able to synthesize hormones but they also have the ability to bind them (Christopher and Sundermann, 1992Christensen et al, 2003;Csaba, 1981;…”

Presence and localization of epidermal growth factor (EGF)‐ and EGF‐receptor‐like immunoreactivity in Tetrahymena

“…It is known that there is an overlap between insulin, EGF and Con-A receptors (Christopher and Sundermann, 1995;Csaba and Kova´cs, 1991;Kova´cs et al, 1987), because of their common origin and similar structure (Obberghen and Gammeltoft, 1987). In mammalian cells, antibodies to the EGFreceptor can also be bound by other glycoproteins, such as the blood group A carbohydrate structure and other glycoproteins from diverse cell types (Gooi et al, 1983(Gooi et al, , 1985. This broad ''specificity'' of the antibody and receptor could be the cause of the obvious, if rare, presence of fluorescent spots seen with the EGFreceptor antibody.…”

Is there a hormonal regulation of phagocytosis at unicellular and multicellular levels? A critical review

“…These unicellular hormones act to cells of metazoa similar to hormones of their own [94]. The unicell also has receptors for mammalian hormones and the receptors' structure is similar to mammalian ones [15,16,95], and can transmit hormonal information into the cells, which provokes response.…”