Labels:text | screenshot | black and white | black | font | document OCR: e widely Basal GH levels are elevated and fluctu but do not correlate well with any clinic tes the I (IGF-I) manifestation of the disease. GH stimul production of insulin-like growth factor invariably, and levels of IGF-I are often, though no elevated in acromegaly (Fig. 3.14). In normal subjects, GH levels are mostl termittent undetectable in the serum, apart from i y ninety pulses of secretion, lasting approximate aring the minutes, which occur five or six times alsatile day and more frequently at night. This s means nature of GH secretion in normal subje between that it may not be possible to distinguish sing basal normal and some acromegalic patients refore GH concentrations; dynamic tests are th necessary.