Effect of suckling and adrenergic stimulation on peripheral deiodination in lactating rats: differential expression of type 1 deiodinase mRNA forms

Abstract

Previous works led us to propose that peripheral iodothyronine deiodination is mainly regulated by the reciprocal interaction between the thyroid and the sympathetic nervous system (SNS). In this study, we analyzed the role suckling exerts, through SNS activation, upon deiodination of thyronines in liver, heart, brown adipose tissue and mammary gland during lactation. Our results showed that resuckling causes a concurrent stimulatory response on deiodinase type 1 (D1) in heart and mammary gland, but not in liver and brown adipose tissue. The stimulatory response was mimicked by norepinephrine and by the -adrenergic agonist isoproterenol, through the overexpression of the large form of D1 mRNA. These results suggested that, during lactation, peripheral thyronine deiodination is co-ordinated by the SNS, and suckling is a major modulatory influence.

Liver 5'-deiodinase activity is modified in rats under restricted feeding schedules: evidence for post-translational regulation

“…changes in mRNA transcription velocity, protein stability, or installation of some covalent mechanism such as phosphorylation or methylation (Mori et al 1996, Roger et al 1997. Moreover, the lack of signal in the long D1 mRNA amplification for all the samples is in agreement with previous work where we demonstrated that the large mRNA form was expressed only in metabolic overdemand situations like chronic hyperthyroidism, lactation or adrenergic stimulation (Aceves & Huidobro 2001), and it suggests that in normal or fasting regimens D1 enzyme is encoded by the short messenger. The low D1 activity measured before food presentation (0800 and 1100 h) was coincident with a significant increase in corticosterone serum levels (Díaz-Muñoz et al 2000), whereas the enhancement in D1 activity after feeding (1400 h) was concurrent with a peak in serum insulin (Díaz-Muñoz et al 2000).…”

“…Moreover, it has been documented that the decrease in D1 activity during fasting is accompanied by a similar decline in D1 mRNA levels, suggesting the existence of pretranslational mechanisms (O'Mara et al 1993). In addition, we have previously reported the encoding of D1 by two messengers that differ in the length of their 3 -untranslated region (3 UTR), and also that the expression of the large form increases with hyperthyroidism in liver and with -adrenergic stimulation in heart and mammary gland (Navarro et al 1997, Aceves & Rojas-Huidobro 2001. Functional studies analyzing the participation of these different messengers have not been undertaken during fasting or catabolic situations.…”

“…Total D1 mRNA (including both short and long messengers) was identified by using a previously standardized semiquantitative PCR procedure in which an amplicon of the structural protein cyclophilin (Cyc) was co-amplified (Aceves & Rojas-Huidobro 2001). To verify the presence of the long form of D1 mRNA a PCR amplification was carried out for 40 cycles with oligonucleotides whose sequences are only present in the 3 UTR of the long mRNA form.…”

Cold exposure restores the decrease in leptin receptors (OB-Rb) caused by neonatal leptin treatment in 30-day-old rats

“…Acute cold regulates leptin receptor a role on these changes. Catecholamine has a stimulatory effect on thyroidal T 3 production (Shimura et al 1990) as well as D1 (Aceves & Rojas-Huidobro 2001) and D2 activities (Silva & Larsen 1983). Also, it mediates the cold-induced suppression of leptin expression (Trayhurn et al 1995).…”

Human Breast Cancer Tissue Expresses High Level of Type 1 5′-Deiodinase

“…In humans, D1 is present mainly in the liver, kidneys, thyroid, and pituitary gland, while D2 is chiefly expressed in the central nervous system, pituitary gland, skeletal muscle, and thyroid (2). There is no data available on D1 expression in healthy human breast tissue or human breast cancer tissue, although a few reports have documented the presence of D1 activity in rat mammary glands or breast cancer in rats (3)(4)(5)(6)(7). To the contrary, decreased D1 activity has been observed in other cancers, such as renal clear cell carcinoma (8), papillary thyroid cancer tissue (9) as well as papillary (10) and follicular (11) thyroid cancer cell lines, lung cancer (12), and in some pituitary tumors (13) when compared to their healthy counterparts.…”