The activities of glycolytic and Krebs cycle enzymes were evaluated to provide an understanding of the extent of glucose metabolic capacity of human preantral follicles and their regulation by gonadotropins and intraovarian growth factors. Under the basal condition, follicular PFK activity was low for both class 1 and class 2 follicles. However, the enzyme activity increased significantly in response to both FSH and LH compared to control (Fig. 1). Cheap Diskus Advair
Whereas LH was more potent than FSH in stimulating PFK activity for class 1 follicles, the opposite was true for class 2 follicles (Fig. 1). Nevertheless, the degree of stimulation by both gonadotropins was greater for class 2 follicles (FSH, 8-fold; LH, 6-fold) than for class 1 follicles (FSH, 2.1-fold; LH, 3-fold). EGF apparently did not influence the activity of PFK for either class (Fig. 1). Whereas IGF-I exerted a negative influence on PFK activity in class 1, a 2-fold stimulation (p < 0.05) was observed for class 2 follicles (Fig. 1). Likewise, TGFp1 significantly stimulated PFK activity in class 1 but had no effect on class 2 follicles. TGFp1 stimulation of PFK activity in class 1 follicles was comparable to the FSH and LH effect (Fig. 1).
FIG. 1. PFK activity in human class 1 (A) and class 2 (B) preantral follicles. Follicles were incubated for 24 h in the presence or absence of gonadotropins or growth factors, and the enzyme activity was determined in the cytosol. Gonadotropins and TGFp1 significantly stimulated PFK activity for class 1, whereas the effect of gonadotropins on class 2 follicles was considerably greater than that of any growth factor. Note a reversal of the FSH and LH effects between class 1 and 2 follicles. Values with the same letter are significantly (p < 0.05) different from each other.