Thyroid Gland Grows in the Cold
in [Thyroid]
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From: Rod on 18 Apr 2008 16:10 I have just come across an interesting paper (see summary/abstract below). Pigs were kept in a cold environment (4 degrees C). This resulted in "increased energy intake, thyroid size, T3 PAR, and hepatic 5'D-I activity with little change in serum TSH". As I understand it, that is basically saying that the pigs responded to the cold by turning the gas up! And the TSH being more or less unchanged shows that they had got it more or less right. So far, so good. But what actually fascinates me is how the pigs react when they get brought back into the warm. Do their thyroids shrink? I assume they must otherwise any pig that has *ever* been cold would already have an enlarged thyroid. What actually happens to make theiir thyroids shrink? Is there any connection between this normal shrinkage and what happens in (atrophic) autoimmune thyroid disease? "Changes in serum triiodothyronine kinetics and hepatic type I 5'-deiodinase activity of cold-exposed swine H. L. Reed, M. Quesada, R. L. Hesslink Jr, M. M. D'Alesandro, M. T. Hays, R. J. Christopherson, B. V. Turner and B. A. Young Department of Medicine, Endocrine Service, Madigan Army Medical Center, Tacoma, Washington 98431-5000. Swine exposed to cold air have elevated serum values of total triiodothyronine (TT3) and free T3 (FT3). To characterize the mechanism of these increases, we measured in vivo kinetic parameters after a bolus intravenous injection of 125I-labeled T3 by use of both multicompartmental (MC) and noncompartmental (NC) methods and in vitro hepatic type I iodothyronine 5'-deiodinase (5'D-I) activity. Ten ad libitum-fed 5-mo-old boars were divided into two groups, living for 25 days in either control (22 degrees C) or cold (4 degrees C) conditions. Cold-exposed animals consumed 50% more calories than control animals but showed no difference in total body weight, percent body fat, or plasma volume. Thyroid gland weight was increased 86% (P < 0.004), as was serum total thyroxine (TT4) (48%), free T4 (FT4) (61%), TT3 (103%), and FT3 (107%), whereas serum thyrotropin (TSH) was not different in cold-exposed compared with control animals. The T3 plasma clearance rate was similar between groups when both MC and NC techniques were used. However, T3 plasma appearance rate (PAR) was elevated in cold-treated animals 110% over controls by MC (P < 0.001) and 83% by NC methods (P < 0.001). The animal total hormone pool of T3 was increased 76% (MC) and 53% (NC) compared with control (P < 0.01). The Michaelis constant of hepatic 5'D-I was not different between groups, but the maximum enzyme velocity increased (106%; P < 0.02). Therefore cold exposure for 25 days is associated with increased energy intake, thyroid size, T3 PAR, and hepatic 5'D-I activity with little change in serum TSH." <http://ajpendo.physiology.org/cgi/content/abstract/266/5/E786> -- Rod Hypothyroidism is a seriously debilitating condition with an insidious onset. Although common it frequently goes undiagnosed. <www.thyromind.info> <www.thyroiduk.org> <www.altsupportthyroid.org>
From: Alan B. Mac Farlane on 18 Apr 2008 22:06 in article 66sdieFm996oU1(a)mid.individual.net, Rod at polygonum(a)ntlworld.com wrote on 4/18/08 1:10 PM: > As I understand it, that is basically saying that the pigs responded to > the cold by turning the gas up! If you look deeper, the pigs responded to the stressors of the environment and the adrenal metabolic fight/flight/freeze response kicked in of the Sympathetic Nervous System. (this is where you get the so called Dolphin Reflex kicking in ... some say 5 hours under water below 55 degrees or so is live AID in the ER or meat wagon if they do it right - also freezing the face makes this Dolphine Reflex kick in another way by slowing the swelling of the brain and spinal cord for neck injuries at high altitude lakes that were ice cold ... if meat wagons got the freon out and did a spray freeze on new head/spinals they could save a lot of secondary damage from happening) So there is good and bad that comes with the traumatic stress response of the psychophysiology of any given sentient moving being ... Ameobias have a fight/flight/freeze system going on ... or on the face of it .... it appears so. The 'gas being turned up' happens in the face of electricity grid zapping the poor monkey or pig on the feet with out let up ... gets the same response, even identical response, as cold that do not let up. It is the constant traumatic stress response will do it ... and if the toddler tantrum is not handled correctly ... then the PTSD settles in with the person hating their mom and dad inside ... thereby making them an addict and a broken family future. Love your mom and dad inside, be free of their prison of fear, and know how to pour love into their wounds ... then you will make good strong medicine, not be an addict, have a mended family, and fix the PTSD issues of your own toddler tantrum. There by making you fit to raise children. Parent obects with PTSD, and are off with their mom and dad inside, full of judgement, expectation, justification, invalidation, shame, criticism, fear, anger locking in their own toddler tantrum ... a PTSD function of the freeze response of the SNS from the chronic traumatic stress of a poor childhood ... are not fit to parent children of course. IMO and all that rot ... sumbuddie wear blind sea :)
From: mikes on 18 Apr 2008 23:20 On Apr 18, 4:10 pm, Rod <polygo...(a)ntlworld.com> wrote: > I have just come across an interesting paper (see summary/abstract > below). Pigs were kept in a cold environment (4 degrees C). This > resulted in "increased energy intake, thyroid size, T3 PAR, and hepatic > 5'D-I activity with little change in serum TSH". > > As I understand it, that is basically saying that the pigs responded to > the cold by turning the gas up! And the TSH being more or less unchanged > shows that they had got it more or less right. These thyroid things look more and more complicated to me. I don't know what to think. Earlier I developed urticaria after swimming in a relatively chilly water (no matter sea or pool). I explained this to myself by the TSH spikes and corresponding autoimmune reaction. Now they say TSH changes insignificantly (but maybe enough to cause skin rash?). Biochemical effects of exposure to cold are very interesting. Leptin is involved there somehow, visceral fat burns etc. You can not see many fat guys in Scandinavia, for example.
From: Rod on 19 Apr 2008 03:37 mikes wrote: > On Apr 18, 4:10 pm, Rod <polygo...(a)ntlworld.com> wrote: >> I have just come across an interesting paper (see summary/abstract >> below). Pigs were kept in a cold environment (4 degrees C). This >> resulted in "increased energy intake, thyroid size, T3 PAR, and hepatic >> 5'D-I activity with little change in serum TSH". >> >> As I understand it, that is basically saying that the pigs responded to >> the cold by turning the gas up! And the TSH being more or less unchanged >> shows that they had got it more or less right. > > > These thyroid things look more and more complicated to me. I don't > know what to think. Earlier I developed urticaria after swimming in a > relatively chilly water (no matter sea or pool). I explained this to > myself by the TSH spikes and corresponding autoimmune reaction. Now > they say TSH changes insignificantly (but maybe enough to cause skin > rash?). Biochemical effects of exposure to cold are very interesting. > Leptin is involved there somehow, visceral fat burns etc. You can not > see many fat guys in Scandinavia, for example. > You are spot on there with the leptin! I just happened to have the abstract below open as I read your post. Way back (couple of years or so ago), when partner was first diagnosed (with autoimmune hypo), I started to read up. As I tried to correlate her symptoms and odd reaction to commencing thyroxine, I became more and more convinced of the involvement of leptin, somatostatin, gastrin, renin, angiotensin and the less-often-mentioned adrenal and other hormones. Just didn't see how things hang together or what to do. For that matter, I still don't, but neither do I believe anyone else does - least of all endocrinologists. I am still bemused by the phrase "the thyroid is the largest endocrine gland" which I read so often in endocrine texts - even recent ones. Handily ignoring the endocrine nature of adipose tissue (producing leptin). (I have a feeling many people have more than 20/25 grams of brown adipose. :-) ) Funny how "they" keep stating with certainty how things work and then come up with whole new hormones and endocrine glands. "Acute cold exposure, leptin, and somatostatin analog (octreotide) modulate thyroid 5'-deiodinase activity Patricia Cristina Lisboa, Karen Jesus Oliveira, Adriana Cabanelas, Tania Maria Ortiga-Carvalho, and Carmen Cabanelas Pazos-Moura Laborat�rio de Endocrinologia Molecular, Instituto de Biof�sica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, 21949-900 Rio de Janeiro, Brazil We investigated the effect of acute cold exposure, leptin, and the somatostatin analog octreotide (OCT) on thyroid type I (D1) and II (D2) deiodinase activities. Microsomal D1 and D2 activities were measured by the release of 125I from 125I-reverse triiodothyronine (rT3) under different assay conditions. Rats exposed to 4�C (15, 30, 60, and 120 min) showed progressive reduction in thyroidal D1 and D2, reaching ~40% at 2 h (P < 0.05) despite increased circulating TSH (P < 0,05) associated with the higher thyroid D1 and D2 in hypothyroid rats. A single injection of leptin (8 �g/100 g body wt sc) induced increased thyroid and liver D1 (P < 0.05), but not thyroid D2, activities at 30 and 120 min, independently of the serum TSH rise shown only at 2 h. OCT (1 �g/kg body wt sc) increased D1 and D2 activity significantly 24 h after a single injection, with no changes in serum TSH. Therefore, leptin and somatostatin are potential physiological upregulators of thyroid deiodinases, and their low secretion during acute cold exposure may be a potential mechanism contributing to cold-induced reduction in thyroid deiodinase activity." <http://ajpendo.physiology.org/cgi/content/abstract/284/6/E1172> -- Rod Hypothyroidism is a seriously debilitating condition with an insidious onset. Although common it frequently goes undiagnosed. <www.thyromind.info> <www.thyroiduk.org> <www.altsupportthyroid.org>
From: AJBP2009 on 19 Apr 2008 22:01
> I am still bemused by the phrase "the thyroid is the largest endocrine > gland" which I read so often in endocrine texts - even recent ones. > Handily ignoring the endocrine nature of adipose tissue (producing > leptin). (I have a feeling many people have more than 20/25 grams of > brown adipose. :-) ) Funny how "they" keep stating with certainty how > things work and then come up with whole new hormones and endocrine glands. You bring up a very good point. It's interesting how they teach such things. I have to mention that in addition to leptin, as you stated, adipose tissue also makes estrogen. The liver's not that small either and also has some endocrine function. It makes insulin-like growth factor, angiotensinogen and angiotensin as well as as well as thrombopoetin. That brings me to think about the pancreas. I don't really know how big it is, but seems like it'd be bigger than the butterfly gland. I could be wrong about that though. Kidneys make some good hormones, too. Then you could go into the pregnant uterus or the placenta! Those are loaded with good stuff also. Hmmm.... I am wondering if those endocrine texts should be more precise in saying organs/tissues with strictly endocrine function (and no other) are.... (fill in). Know that you're making me think of a bunch of other questions on this brain fog Saturday night in Pennsylvania (I'm stateside now!). I'm still paying for hauling luggage, a cat and an overstuffed computer bag yesterday flying our not-so-friendly skies. Have had a few naps today, but I'm looking forward to tomorrow being a better day. That being said, I'm not sure how much sense I'm making right now. Anyway, before I rambled on (and I may be about to ramble on again...), I was thinking about how we talk about the thyroid making T4 and T3.... and then I remembered it also makes Calcitonin (and is also supposed to be found in Armour as we all know from our Armour discussions). So.......... ok here we go with crazy thyroid glands and what they do and don't do. I don't hear much discussion on Calcitonin and thyroid. Does anyone have any comments about this? Does anyone have a calcitonin shortage or derangement with all of our thyroid business? Ok, here's another question coming from brain fog. In reference to the no change in TSH value in the pigs.... I realize that TT4 and FT4 were elevated. Does the thyroid gland also STORE T4 instead of just making as needed? Then somehow it maybe releases it in response to TSH, which self corrects its level fairly quickly (in pigs)? Maybe the hypertrophy comes from its "busy-ness" of making more to anticipate the same environmental conditions (lasting longer then the 25 days)? Those T3s increasing are just from increased demand and conversions, and there is a domino effect it would seem to me...? Also, I'd be curious to know if the hypertrophied thyroid involuted over a certain time following the research (if the pigs lived that long)? I doubt they kept the pigs long enough for that though, but it would have been interesting to see. |