Basal Hormone Levels

Measuring serum FSH on cycle day 3 is probably the most widely used invasive test to measure ovarian reserve (S8, T4). When natural cycles are monitored, follicular growth rate is slower in young women with high FSH levels compared to controls with normal FSH levels (Al). In natural IVF cycles, raised FSH is associated with an increase in cancellation rates for poor follicular development, although 

Cancellation rates are higher in women with high FSH levels (G8, S10, S19, T5). This is possibly due to a poorer response, since peak estradiol concentrations are lower in women with elevated FSH levels (Cl, El, G8, H16, Ml 1, R2, S10, T5). Some studies find no difference in cycle failures between patients with elevated and those with normal FSH levels (El). This can be explained by the fact that different IVF programs have different reasons for cycle cancellation. 

Some studies find a higher total number of ampoules of FSH administered before oocyte retrieval in patients with elevated FSH levels (SI9), but others do not (Cl, El, H16, S10). When the influence of age and FSH is compared, FSH is a better predictor for response in assisted reproduction than age (Cl, G8, T5), although this is not the case for predicting pregnancy in all studies (HI, S19). 

Usually, basal FSH is measured on cycle day 3. Hansen et al., however, found no statistical difference in FSH levels on cycle days 2, 3, 4, and 5 (H3). It seems that within this time range, any moment is appropriate to determine basal FSH. However, as estradiol levels raise significantly during this early follicular stage, caution must be taken in interpreting FSH levels as normal, because raised estradiol levels may suppress FSH concentrations (S22). 

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R16. Ross, R., Miell, J., Freeman, E Jonest, J., Matthews, D., Preece, M and Buchanan, C, Critically ill patients have high basal growth hormone levels with attenuated oscillatory activity associated with low levels of insulin-like growth factor-I. Clin. Endocrinol. 35,47-54 (1991). 

Endocrine effects Statins interfere with cholesterol synthesis and lower circulating cholesterol levels and, as such, might theoretically blunt adrenal or gonadal steroid hormone production. Small declines in total testosterone with no commensurate elevation in LH have been noted with the use of fluvastatin. Pravastatin showed inconsistent results with regard to possible effects on basal steroid hormone levels atorvastatin, lovastatin, rosuvastatin, and simvastatin did not reduce basal plasma cortisol concentration or basal plasma testosterone concentration or impair adrenal reserve. Appropriately evaluate patients who display clinical evidence of endocrine dysfunction. Exercise caution when administering HMG-CoA reductase inhibitors with drugs that affect steroid levels or activity, such as ketoconazole, spironolactone, and cimetidine. 

H16. Huyser, C., Fourie, F. L., Pentz, J., and Hurter, P., The predictive value of basal follicle stimulating and growth hormone levels as determined by immunofluorometry during assisted reproduction. J. Assist. Reprod. Genet. 12, 244—251 (1995). 

Stanger, J. D., and Yovich, J. L., Reduced in-vitro fertilization of human oocytes from patients with raised basal luteinizing hormone levels during the follicular phase. Br.J. Obstet. Gynaecol. 92, 385-393 (1985). 

Tl. Tanbo, T., Dale, R O., Lunde, O., Norman, N., and Abyholm, T., Prediction of response to controlled ovarian hyperstimulation A comparison of basal and clomiphene citrate-stimulated follicle-stimulating hormone levels. Fertil. Steril. 57, 819-824 (1992). 

T5. Toner, J. P., Philput, C. B., Jones, G. S., and Muasher, S. J., Basal follicle-stimulating hormone level is a better predictor of in vitro fertilization performance than age. Fertil. Steril. 55,784-791 (1991). 

Recombinant human growth hormone (hGH) is a 22-kDa protein drug having 191 amino acids. It has been used to treat a number of conditions, including short stature in children, Turner syndrome, and chronic renal failure. It is said to play an important role in the metabolism of proteins, carbohydrates, and fats as well as electrolytes and hence influences weight and height. It has been reported that hGH secretion in humans is pulsatile, showing low basal serum levels in between peaks. It has been... 

An increase in thyroid hormone levels results in an increase in the basal metabolic rate (BMR). BMR measurements can be used to assess thyroid status, as discussed in detail in Chapter 5. This method for the diagnosis of hypo- or hyperthyroidism is not in coitimon use because it is cumbersome. The increase in BMR has been associated with increases in various reactions that use ATP. The increased use of ATP is matched by an increase in activity of the respiratory chain and in Oj... 

Lastly, we address insulin delivery to which much effort has been dedicated. While the insulin spikes required postprandially may be difficult to achieve with iontophoresis, the method may have the potential to mimic the physiological, nearly constant, basal secretion (1 lU/h) of the hormone, which is observed in the non-diabetic adult (i.e., a requirement that is not provided by intermittent subcutaneous injections). A recent, excellent review ° of the work performed (almost exclusively in animal models) concludes that while insulin iontophoresis can be sufficient to treat a small diabetic animal, the best deliveries achieved are still 1-2 orders of magnitude below that necessary to meet the basal secretion level in humans. It seems unlikely, therefore, that we will see an insulin iontophoretic delivery system on the market in the foreseeable future. 

FIGURE 4.9 Plasma glucose and hormone levels before, during, and after insulin infusion. Normal human subjects were infused with insulin for the 1-hour period indicated by the black bar. Glucose, insulin, smd glucagon levels were measured at the indicated times. While plasma insulin increased to six times its basal level, plasma glucose fell precipitously and plasma glucagon rose. (Redrawn with permission from Bolli et al, 1984.)... 

Fig. 5. Blood glucose and plasma counter-regulatory hormone levels before, during and after a constant intravenous insulin infusion. = P 0.05 versus basal 0= n.s. versus basal. (Source Bolli et al., 1984c.)...

Winer, L.M., M.A. Shaw, and G. Baumann (1990). Basal plasma growth hormone levels in man New evidence for rhythmicity of growth hormone secretion. J. Clin. Endocrinol. Metab. 70, 1678—1686. 

To establish the diagnosis of a secretory tumor of an endocrine gland, one must first demonstrate that basal serum levels of the hormone in question are regularly elevated. More importantly, one must show that the hypersecretion of the hormone (and, hence, its elevated level in the peripheral blood) cannot be adequately inhibited by "maneuvers" that are known to suppress secretion from a normally functioning gland (i.e., one must show that the hypersecretion is "autonomous"). 

It is evident that variations in thyroid hormone levels are among the main physiological modulators of in vivo cellular oxidative stress. The hypermetabolic state in hyperthyroidism is associated with increases in free radical production and lipid peroxidation (LP), and the hypomet-abolic state in hypothyroidism is generally associated with a decrease in free radical production and LP in most tissues (Fernandez et ai, 1985 Venditti et ai, 1997). The development of a hyperthyroid state in vertebrates leads to enhancement of their basal metabolic rate due to an increase in the rate of O2 consumption in most tissues, excluding the spleen, testis and adult brain (Barker and Klitgaard, 1952). Thyroid hormones were shown... 

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