Macrina Mason

Distribution of growth hormone isoforms in sera from women with normal ovarian function, galactorrhea, and normoprolactinemia *

OBJECTIVE To demonstrate if GH concentrations and molecular heterogeneity of GH correlates with the presence of galactorrhea in normoprolactinemic women with normal ovarian function. DESIGN Aliquots of sera from women with normal ovarian function and normoprolactinemic galactorrhea were subjected to gel filtration chromatography, and the fractions were assayed for GH by the use of radioimmunoassay. Molecular weight of isoforms was calculated on a calibration curve obtained with molecular markers. The molecular variants were characterized on the basis of elution volume, molecular weight (MW), and partition coefficient. RESULTS Basal serum GH levels were moderately elevated in all six normoprolactinemic women exhibiting galactorrhea. Chromatographic study of sera from these normoprolactinemic women showed the predominance of 40 to 50 kd molecular forms of GH as well as some very low MW GH isoforms. This pattern was different from that obtained in sera from normal women without galactorrhea who presented a predominance of heavier (> 60 kd) isoforms eluted before the GH labeled standard. The monomeric forms were present in less proportion but there was no significant difference as compared with galactorrheic group. CONCLUSIONS Our investigation demonstrated elevated GH basal serum levels is normoprolactinemic women with galactorrhea, and chromatography in gel showed a low proportion of the large MW GH variants associated with a higher proportion of the dimeric forms and very low MW forms of GH. This is different from normal women without galactorrhea who had a predominance of heavier MW GH variants and lesser proportion of < 16 kd isoforms. It is concluded that an increased GH secretion may be responsible for abnormal lactation despite normal PRL levels in some women with normal ovarian function.

Distribution of follicle-stimulating hormone and luteinizing hormone isoforms in sera from women with primary ovarian failure compared with that of normal reproductive and postmenopausal women**Supported in part by grant P219CCOL880122 from the Consejo Nacional de Ciencia y Tecnología de México, Mexico, D.F., México.

OBJECTIVE To demonstrate if molecular heterogeneity of gonadotropins correlates with the type of primary gonadal failure. DESIGN AND METHODS Aliquots of sera from women with hypogonadism were subjected to gel filtration chromatography to be assayed for follicle-stimulating hormone (FSH) and luteinizing hormone (LH) by the use of radioimmunoassay. Molecular weight (MW) of isoforms was calculated on a calibration curve obtained with molecular markers. The molecular variants were characterized on the basis of elution volume, MW, and partition coefficient. RESULTS Chromatographic profile of sera from four women with natural menopause exhibited two FSH peaks of immunoreactivity and a heavier LH isoform. This pattern was different from that obtained in sera from women of reproductive age who presented a single peak that eluted after the corresponding standard. In six cases of idiopathic premature menopause and three more with gonadotropin-resistant ovary, the chromatographic profile showed a marked and remarkable molecular heterogeneity, particularly LH, and this was more apparent in women with resistant ovary. CONCLUSIONS Our investigation confirms the relationship between the gonadotropin heterogeneity with the gonadal failure. The duration of the ovarian failure may influence the molecular proportion of gonadotropins and the predominance of heavier MW isohormones.