Glucose Ingestion Acutely Lowers Testosterone

[Michael Scally MD]

High body-mass index (BMI), advancing adult age, chronic renal failure, metabolic syndrome X, prolonged fasting, weight loss, sustained hyperglycemia, acute hypoglycemia and diabetes mellitus are associated with decreased testosterone (T) concentrations and variable suppression of LH secretion. Intraabdominal adiposity, hyperinsulinism, metabolic syndrome and/or glucose intolerance are possible common substrates in the pathophysiology of these conditions.

For example, excessive abdominal visceral fat (AVF) is accompanied by reductions in LH pulse amplitude, total T and SHBG concentrations. Insulin resistance and impaired glucose tolerance are concomitants of visceral adiposity. However, their individual and joint roles in hypoandrogenemia are difficult to quantify precisely. Although in vitro studies indicate that IGF-I and insulin can potentiate hCG-stimulated T secretion, and adipocytokines like leptin and adiponectin can suppress T secretion, clinical data are contradictory and inconsistent.

In one study, insulin resistance correlated inversely with the maximal serum T concentration after hCG injection, whereas in another study a 6-h euglycemic hyperinsulinemic clamp did not alter LH or free T concentrations in men. In earlier investigations, an insulin clamp increased T levels in obese men; insulin sensitivity correlated positively with free T concentrations in young men; oral glucose, rosiglitazone, metformin and diazoxide reduced T and either did not affect or elevated LH concentrations; and weight loss in obese men increased both T and LH levels.

Beyond inconsistency of inference, laboratory and clinical data have other major limitations. First, available studies have not controlled for intersubject variability in age, BMI, AVF, fasting plasma glucose, insulin, leptin and adiponectin concentrations. Second, earlier investigations did not directly compare the effects of glucose loading with those of calorie-free liquid ingestion at the same time of day in the same individuals. And, third, the dynamic bases for LH and T changes have not been quantified by frequent blood sampling and modern analytical tools, leaving the mechanism(s) of any acute oral-glucose effects open to question.

The present investigation addresses these limitations in a cohort of 57 healthy men ages 19-78 yr by intraindividual comparison of water vs oral glucose ingestion at the same time of day, 10-min blood sampling for 6.5 h, deconvolution analysis of LH and T secretion, and analytical dose-response estimation. This design allowed assessment of the interactive effects of glucose and age on LH/T secretion.

In summary, oral glucose administration acutely lowers LH and total T concentrations by suppressing pulsatile LH secretion and basal T secretion commensurately, with no significant change in the calculated LH-T dose-response function. Regression analyses suggest that adiponectin and insulin may have respectively protective and exacerbating effects on the acute LH/T fall after oral glucose administration in men.


Iranmanesh A, Lawson D, Veldhuis JD. Glucose Ingestion Acutely Lowers Pulsatile LH and Basal Testosterone Secretion in Men. American Journal of Physiology - Endocrinology And Metabolism. http://ajpendo.physiology.org/content/early/2012/01/12/ajpendo.00520.2011.abstract (Glucose Ingestion Acutely Lowers Pulsatile LH and Basal Testosterone Secretion in Men)

Chronic hyperglycemia inhibits the male gonadal axis. The present analyses test the hypothesis that acute glucose ingestion also suppresses LH and testosterone (T) secretion, and blunts the LH-T dose-response function. The design comprised a prospectively randomized crossover comparison of LH and T secretion after glucose vs water ingestion in a Clinical Translational Research Center. The participants were healthy men (N=57) ages 19-78 yr with body mass index (BMI) 20-39 kg/m2. Main outcome measures were deconvolution and LH-T dose-response analyses of 10-min data. LH-T responses were regressed on glucose, insulin, leptin, adiponectin, age, BMI and CT-estimated abdominal visceral fat (AVF). During the first 120 min after glucose ingestion, for each unit decrease in LH concentrations T concentrations decreased by 86 (27-144) ng/dL (R=0.853, P<0.001). Based upon deconvolution analysis, glucose compared with water ingestion reduced (i) basal [nonpulsatile] (P<0.001) and total (P<0.001) T secretion without affecting pulsatile T output, and (ii) pulsatile (P=0.043) but not basal LH secretion. By multivariate analysis, pulsatile LH secretion positively predicted basal T secretion after glucose ingestion (R=0.374, P=0.0042). In addition, the glucose-induced fall in pulsatile LH secretion was exacerbated by higher fasting insulin concentrations (P=0.054), and attenuated by higher adiponectin levels (P=0.0037). There were no detectable changes in the analytically estimated LH-T dose-response curves (P>0.30). In conclusion, glucose ingestion suppresses pulsatile LH and basal T secretion acutely in healthy men. Suppression is influenced by age, glucose, adiponectin and insulin concentrations.

 

[BBC3]

Re: Glucose Ingestion Acutely Lowers Pulsatile LH and Basal Testosterone Secretion

Good stuff. I would like the full article if you can send... Pleauuzzz..

But they just said not to have a sugar/protien shake while working out!!! They are saying spike sugar and one can not produce "on demand" LH & TT... But you can sit on your ass and no effect.....?

First, SO LETS TALK SERUM COUNTS... If they are stimulusing with physical exhertion, then PERHAPS TT is INDEED SPIKING BUT BEING USED ON DEMAND........... Thus the measured "fall" in TT. The LH "fall" could be attributed to the LH being uptaked be the testicles as well..... FOREMOST - perhaps not only is LH & TT still pulsing, but being used rather efficiently by these HEALTHY idividuals at the time of demand. Hence the dynamics of the human body and the hormone system. AND PROOF THAT STEROIDS INDEED ARE NEEDED TO SUPPLEMENT THE STIMULUS ACTIVITY TO REMAIN "BASAL" or adequately supplied.....

Second, the article uses terms like "secretion" which connotate they are measuring output. But be clear there is no meter hooked up to the testicle. They are measuring blood levels WHICH ARE SUBJECTIVE TO A SUBJECTS DEMANDS & USAGE. Which most obviously is directily corrolated to Androgen and Estrogen PRODUCTION FACTORS. So what were the differences based on obesity and activity levels? Did the fatter guy have a larger shutdown, or smaller? But what was his anfrogenic propensity as well.. ITS ABOUT OVERALL DEMANDS... If there is hormone in the blood - there is no proof that ALL demands at the receptors are not being met by blood serum measure alone REGARDLESS....

What is the "Unit of LH" they speak of elliciting the 84 point drop in TT? Is it the (.384)???

So in summary:

First they are somehow distinguishing between Basal (steady or resting or status quo??) levels and PULSATILE LEVELS?!?!?! What pulse? Are they actively "Stress testing" the subjects? And by what means? Exercise, anger, a hair pie in their face?? They say eat sugar and your abitily to pluse LH and TT diminish by 84 TT points per .384 count of LH... ?? They say the subjects are "healthy", but make no mistake they would appear to have fatties too. A BMI index 20-40 basically?? Thats a 6ft tall make weighing anywhere from 165-300lbs. I would like to see if weight was QUALIFIED.... They did say that higher Adinponectin (Fat produced) levels attenuate (prolong) the drop in the ability to "on demand" LH & TT. Hmmm, again, fat could just be eating MORE TT(for estrogen) than Muscle.... They also said that higher base line insulin levels made the degree of the Drop in TT and LH worse ( a bigger number). Again, sugar>insulin>TT>estrogen>to FAT. More fat taking more TT.....

!!!!! So really. what number in LH actually corrolated with the 84 count TT decrease.?? This is the most important thing in this whole study and the only APPLE FOR APPLE HERE... Was is .384. or what was it. Cause that is interesting...! (and again proof that HCG is only an Agonist and not a mimicer) but I wont got there now....

!!!!! How are they discerning the difference between basal & pulsitile??

!!!!! Without a flow meter on the nutz the have Nothing.....

!!!!! Without knowing whether the subjects muscle is (a) currently active, (b) genetically dense with androgen receptors, (c) or accounting for Bone structure - is a massive failure.

!!!! Its a massive failure to present this study as male and therefore "testosterone = androgens" which is furthest from the truth.

!!!!! Finally, I believe it makes a difference whether or not a subject is currently (A) storing fat, or (b) in good healthy physical flux hormonally, or (totally training and releasing fat stores... I believe this is critical in determining whether its FAT or MUSCLE that is DEMANDING the TT. To deliver the protien to unlock the cellular activity at muscle, bone, or fat(which creates conversion demand in first place. - and Free T is really only waste product for tissue and the primary factor for feeding the CNS. - Wont go there either.....

!!!!! But the biggest again is SERUM COUNTS,and using this as a vehicle to qualify a research study. But this depends on their method of distinguishing Basil and pulse again. It doesnt matter anyway. FAT, BONE, MUSCLE, & CNS all run on TT. If there is a drop of TT left in the blood, they are getting what they WANT... And when you consider how much TT is spent in just oe second, for anyone to claim that they can measure a change, and without measureing rates of production at the source (testicles), and rates of usage and the demanding factors (receptors), and forget about cross conversion and production points other than the testicles, IS INSANITY..........

Whats that LH unit of measure they used again??

 

[Michael Scally MD]

High-normal Glucose Levels Are Associated with Decreased Testosterone Levels

Shin JY, Park EK, Park BJ, Shim JY, Lee HR. High-normal Glucose Levels in Non-diabetic and Pre-diabetic Men Are Associated with Decreased Testosterone Levels. Korean J Fam Med 2012;33(3):152-6. http://synapse.koreamed.org/Synapse/Data/PDFData/0001KJFM/kjfm-33-152.pdf

BACKGROUND: Testosterone levels are decreased in diabetic patients and recent studies have suggested that high-normal fasting glucose is a risk factor for cardiovascular disease. To further elucidate the relationship between plasma glucose and testosterone, we investigated the association between fasting plasma glucose (FPG) and endogenous sex hormones (serum total testosterone, sex hormone binding globulin, estradiol, and the ratio of testosterone to estradiol) in non-diabetic and pre-diabetic men.

METHODS: This study included 388 men (age >/= 40 years) who visited the health promotion center of a university hospital from May 2007 to August 2008. The subjects were divided into quartiles based on their FPG levels and correlation and multiple linear regression analyses were performed. Q1 (65 mg/dL </= FPG < 88 mg/dL), Q2 (88 mg/dL </= FPG < 94 mg/dL), Q3 (94 mg/dL </= FPG < 100 mg/dL) and Q4 (100 mg/dL </= FPG < 126 mg/dL). RESULTS: FPG was independently, inversely associated with total testosterone in the non-diabetic population after adjusting for age, body mass index, smoking, and alcohol consumption (beta = -0.082, P < 0.01). Among the quartiles, subjects in the high-normal FPG groups (Q2, Q3, and Q4 with FPG >/= 88 mg/dL) had significantly decreased testosterone levels when compared with subjects in the normal FPG group (Q1 with FPG < 88 mg/dL, P < 0.005). Sex hormone binding globulin, estradiol and the ratio of testosterone to estradiol were not correlated with FPG.

CONCLUSION: Our study indicates that high-normal fasting glucose levels are associated with decreased testosterone levels in non-diabetic and pre-diabetic men.

 

[Dr JIM]

Re: High-normal Glucose Levels Are Associated with Decreased Testosterone Levels

Very interesting study especially since a relationship (lowered T level) existed even in the, Q-2 group, whom had clearly normal BS levels!

 

[idmd]

Very interesting study especially since a relationship (lowered T level) existed even in the, Q-2 group, whom had clearly normal BS levels!

Begs the question if that's really a normal BS level.

 

[Dr JIM]

Re: High-normal Glucose Levels Are Associated with Decreased Testosterone Levels

I'm certainly not aware of any lab that would use a reference range blood sugar of less than 95 anything but normal.

 

[idmd]

I'm certainly not aware of any lab that would use a reference range blood sugar of less than 95 anything but normal.

I hear you...and I know that's normal but if we want lab numbers to be meaningful then above a certain number there should be significantly more disease and below that number significantly less. Presumably this is true for type 2 DM. This may not be the case for low T.

I know a PhD who sat on the original committee at the AHA who decided the total cholesterol cutoff of 200. Thing is at the time the data didn't point to 200. It pointed to 250...above 250 there was a statistically significant increase in CVD and below 250 there was less. He argued his point until he was dismissed from the committee.

My point is these ranges should represent some real world increase in disease (or disease risk)...perhaps at a fasting glucose of 97 your risk of type 2 DM isn't significantly higher but if your risk of hypogonadism is higher I'd hardly call 97 normal.

Now I know that's not what this single study justifies but it may be pointing towards something significant enough to reconsider "normal" fasting BS.

 

[Michael Scally MD]

Re: High-normal Glucose Levels Are Associated with Decreased Testosterone Levels

Caronia LM, Dwyer AA, Hayden D, Amati F, Pitteloud N, Hayes FJ. Abrupt Decrease in Serum Testosterone Levels After an Oral Glucose Load in Men: Implications for Screening for Hypogonadism. Clin Endocrinol (Oxf). Abrupt Decrease in Serum Testosterone Levels After an Oral Glucose Load in Men: Implications for Screening for Hypogonadism - Caronia - Clinical Endocrinology - Wiley Online Library

OBJECTIVE: This study examines the physiological impact of a glucose load on serum testosterone (T) levels in men with varying glucose tolerance (GT).

DESIGN: Cross-sectional study

PATIENTS AND METHODS: 74 men (19-74 years, mean 51.4 +/- 1.4 years) underwent a standard 75g oral glucose tolerance test with blood sampling at 0, 30, 60, 90, and 120 min. Fasting serum glucose, insulin, total T (and calculated free T), LH, SHBG, leptin and cortisol were measured.

RESULTS: 57% of the men had normal GT, 30% had impaired GT, and 13% had newly diagnosed type 2 diabetes. Glucose ingestion was associated with a 25% decrease in mean T levels (delta = -4.2 +/- 0.3 nmol/L, p <0.0001). T levels remained suppressed at 120 minutes compared to baseline (13.7 +/- 0.6 vs. 16.5 +/- 0.7 nmol/L, p <0.0001) and did not differ across GT or BMI. Of the 66 men with normal T levels at baseline, 10 (15%) had levels which decreased to the hypogonadal range (<9.7 nmol/L) at one or more time points. SHBG, LH, and cortisol levels were unchanged. Leptin levels decreased from baseline at all time points (p <0.0001).

CONCLUSIONS: Glucose ingestion induces a significant reduction in total and free T levels in men, which is similar across the spectrum of glucose tolerance. This decrease in T appears to be due to a direct testicular defect but the absence of compensatory changes in LH suggests an additional central component. Men found to have low non-fasting T levels should be reevaluated in the fasting state.

 

[imrj]

it amazes me to see the amount of medical researtch that goes into demostrating how things dont work with the knowns negative impact of things like high glucose, fat, etc ,etc..

but its shocking how there is literally zero studies on why this bad things arent a problem for everyone or better yet, they arent a problem at all when we are young.....i can guarantee you someone <20yo can ingest all the glucose and their T will still be high, with high energy and high libido......but no one can explain that, why does it still work when it isnt suppose to.....oh well....maybe one day

 

[ergomaniac]

it amazes me to see the amount of medical researtch that goes into demostrating how things dont work with the knowns negative impact of things like high glucose, fat, etc ,etc..

but its shocking how there is literally zero studies on why this bad things arent a problem for everyone or better yet, they arent a problem at all when we are young.....i can guarantee you someone <20yo can ingest all the glucose and their T will still be high, with high energy and high libido......but no one can explain that, why does it still work when it isnt suppose to.....oh well....maybe one day

aging. its a disease, so to speak.
high blood sugar also blunts gh.
fasting may or may not aleviate some symptoms. high blood sugar is not good all the time. so cycle your diet. including a https://thinksteroids.com/community/threads/134323454
and can aging be reversed. to some extent anyway.
for health and lean body mass, i say what and when you eat is incredibly overlooked.

 

[Michael Scally MD]

[OA] Oral Glucose Load and Mixed Meal Feeding Lowers Testosterone Levels

PURPOSE: Precise evaluation of serum testosterone levels is important in making an accurate diagnosis of androgen deficiency. Recent practice guidelines on male androgen deficiency recommend that testosterone be measured in the morning while fasting.

Although there is ample evidence regarding morning measurement of testosterone, studies that evaluated the effect of glucose load or meals were limited by inclusion of hypogonadal or diabetic men, and measurement of testosterone was not performed using mass spectrometry.

METHODS: Sixty men (23-97 years) without pre-diabetes or diabetes who had normal total testosterone (TT) levels underwent either an oral glucose tolerance test (OGTT) or a mixed meal tolerance test (MMTT) after an overnight fast. Serum samples were collected before and at regular intervals for 2 h (OGTT cohort) or 3 h (MMTT cohort). TT was measured by LC-MS/MS. LH and prolactin were also measured.

RESULTS: TT decreased after a glucose load (mean drop at nadir = 100 ng/dL) and after a mixed meal (drop at nadir = 123 ng/dL). Approximately 11% of men undergoing OGTT and 56% undergoing MMTT experienced a transient decrease in TT below 300 ng/dL, the lower normal limit. Testosterone started declining 20 min into the tests, with average maximum decline at 60 min. Most men still had TT lower than baseline at 120 min. This effect was independent of changes in LH or prolactin.

CONCLUSION: A glucose load or a mixed meal transiently, but significantly, lowers TT levels in healthy, non-diabetic eugonadal men. These findings support the recommendations that measurement of serum testosterone to diagnose androgen deficiency should be performed while fasting.

Gagliano-Juca T, Li Z, Pencina KM, et al. Oral glucose load and mixed meal feeding lowers testosterone levels in healthy eugonadal men. Endocrine 2019;63:149-56. Oral glucose load and mixed meal feeding lowers testosterone levels in healthy eugonadal men